United States Patent: 3601605

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( 8518 of 8518 )

United States Patent	3,601,605
Elder , et al.	August 24, 1971

CAB SIGNAL AND SPEED CONTROL FOR LOCOMOTIVES

Abstract

Each locomotive in a railroad classification yard area is provided with both cab signal and automatic speed control apparatus, each element controlled at different times from a remote location. The cab signal or speed commands are transmitted to a locomotive by one or a combination of selected tone signals modulated on a carrier signal. Remote control of all cab signals may be by the humpmaster but normally one locomotive is assigned to humping operations and control of its cab signal transferred to the hump conductor. Remote automatic speed control can be established on a locomotive only when it is assigned to humping operations. That locomotive speed control apparatus is then controlled by transmitted tone combinations corresponding to speed selections made by the humpmaster. The locomotive engineer must acknowledge a received automatic operation request in order to establish the remote control condition on the locomotive. The engineer retains an ability to restore local onboard control at any time and has final control of reestablishing automatic operation after any interruption.

Inventors:	Elder; John Calvin (N/A), KUZMICH; William C. (N/A), VAUGHN; Thomas C. (N/A, PA)
Assignee:	Company; Westinghouse Air Brake (PA)
Appl. No.:	04/853,699
Filed:	August 28, 1969

Current U.S. Class: 246/122R ; 246/182R; 340/12.22

Current International Class: B61L 17/00 (20060101); B61L 3/00 (20060101); B61L 3/12 (20060101); B61L 003/00 ()

Field of Search: 246/182R,23,63,187,4,6 325/55,64

References Cited [Referenced By]

U.S. Patent Documents


3096056	July 1963	Allison
3140068	July 1964	Matthews
3441858	April 1969	Graham

Primary Examiner: Point; Arthur L. La
Assistant Examiner: Libman; George H.

Claims

Having thus described my invention, what I claim is:

1. In a railroad classification yard, including a humping track over which cars are moved for selective classification, a system for controlling the operation of the hump locomotive, comprising in combinations,

a. signal transmitting means on the wayside for transmitting over a predetermined channel combinations of a plurality of tones as operating commands to said hump locomotive,

b. a cab signal indication selector means on said wayside operable, and normally connected, for controlling said signal-transmitting means to actuate the transmission of selected tone combinations designating desired cab signal indications,

c. a locomotive speed selector means on said wayside connected to said signal-transmitting means at selected times to bypass said cab signal selector means and operable at said times for controlling said transmitting means to actuate the transmission of other selected tone combinations designating desired speed ranges for the remote control of said locomotive,

d. automatic control selection means on said wayside operable at said selected times to a remote locomotive speed control condition and connected for transferring at said times the control connections of said transmitting means from said cab signal selector means to said speed selector means,

e. a receiver means on said locomotive coupled for receiving and registering the tone combination transmitted by the signal transmitting means,

f. speed control means on said locomotive connected for controlling the speed of that locomotive and selectively operable to a manual and a remote control condition,

1. said speed control means coupled to said receiver means and responsive to the received tone combination only when actuated into the remote control condition for controlling the locomotive speed in accordance with that combination,

g. the operation of said speed selector means following a transfer of the control connections of said transmitting means to said speed selector means actuating the transmission of a distinct initial signal request for establishing a remote control condition of said speed control means,

h. an acknowledging means on said locomotive connected to said receiver means and said speed control means and operable only when an initial signal has been registered for establishing the remote control condition of said speed control means, and

i. cab signal apparatus on said locomotive connected to said receiver means and responsive to registered tone combinations in the absence of an established remote control condition for guiding a locomotive operator in controlling said locomotive.

2. A hump locomotive control system as defined in claim 1 in which said combination further includes,

a. detector means in said humping track for detecting the immediate approach of a train being classified,

b. said detector means connected for completing the connections of said speed selector means to said signal transmitting means only when a train is detected in the immediate approach on said humping track.

3. A hump locomotive control system as defined in claim 1 in which said acknowledging means comprises:

a. a registry relay controlled by said receiver means for temporarily registering the reception of an initial signal,

b. acknowledging devices operable for actuating the storage of a received initial signal,

c. a storage means controlled by said registry relay and said acknowledging devices for storing an initial signal registry when that signal has been received and said devices have been operated, and

d. a stick circuit for said registry relay effective for holding the temporary registry of an initial signal until its storage is actuated if the transmission of another tone combination prematurely replaces said initial signal prior to the operation of said devices.

4. A hump locomotive control system as defined in claim 3 in which said storage means includes,

a. a stick relay controlled by said acknowledging devices and said registry relay for receiving and holding said temporarily registered initial signal when said devices are operated,

b. a stop signal relay controlled by said receiving means and responsive to the absence of all tones,

c. a memory relay controlled by said stick relay for storing an indication of an initial signal storage and by said stop signal relay for holding said indication as long as any tone combination is thereafter received, and

d. a supplemental circuit for said registry relay jointly controlled by said stick relay, said stop signal relay, and said memory relay for reentering an initial signal registry if the acknowledgment of the previous registry is withdrawn while any tone combination continues to be received.

5. A hump locomotive control system as defined in claim 4 in which said system combination further includes a temporary stop control means comprising,

a. a control circuit connection responsive to the operation of said cab signal selector means to a stop condition, when said automatic control means is in its speed control condition, for interrupting the control of said transmitting means by said speed selector means to halt the transmission of all tone combinations and activate a temporary stop condition on the hump locomotive,

b. a temporary stop register means controlled by said cab signal selector means and said automatic control means for registering the temporary stop condition,

1. said stop register means controlled for retaining said stop condition registry while said tone transmission is halted,

c. a signal control circuit jointly controlled by said cab signal selector means and said stop register means and completed, when a stop condition registry exists, in response to the operation of said cab signal selector means out of the stop position to its initial position, for actuating the transmission of another initial signal combination and for restoring control of said transmitting means to said speed selector means.

6. In a railroad classification yard system including, a track lead with a hump over which trains are moved for classification, a plurality of switching locomotives each assignable to humping operations, wayside signals along said track lead for displaying a selected one of a plurality of signal indications to at times direct the movement of the assigned hump locomotive; a hump locomotive movement control system comprising in combination,

a. a first wayside control means having connections to said wayside signals and selectively operable for controlling the signal indication displayed to direct the desired manually controlled movement of the assigned hump locomotive,

b. signal-transmitting means at the wayside for transmitting when actuated selected signal combinations to each locomotive, each combination being receivable only by the corresponding locomotive,

c. a second wayside control means operable for selecting one of said plurality of locomotives for humping operations and for completing control connections between said first control means and said transmitting means by which the transmission of signal combinations receivable by only the selected humping locomotive may be actuated by said first control means to also direct the manually controlled movements of that locomotive,

d. speed control means on each locomotive for at times automatically maintaining the movement of the corresponding locomotive within a selected one of a plurality of predetermined speed ranges,

e. signal-receiving means on each locomotive for selectively receiving from said transmitting means only the signal combinations intended for the corresponding locomotive and having connections to the associated speed control means for at said times selecting one speed range of said plurality of speed ranges in response to the received signal combination,

f. a third wayside control means operable for transferring the control connections of said signal-transmitting means from said first control means to said third control means and connected for immediately thereafter actuating said transmitting means to transmit an initial request signal combination to the selected hump locomotive,

g. said third wayside control means subsequently operable to select different ones of said predetermined speed ranges and controlling said transmitting means to actuate the transmission of signal combinations corresponding to the existing selected speed range, and

h. acknowledging means on each locomotive controlled by the corresponding receiving means for indicating the reception of an initial request signal by that locomotive and operable thereafter for activating the control of the associated speed control means by the corresponding receiving means.

7. A hump locomotive movement control system as defined in claim 6, in which said combination further includes,

a. a train detector in said track lead immediately in approach to said hump operable for detecting the approach of a train to be classified,

b. said train detector connected for controlling said third control means to complete its connections to said transmitting means only when the approach of a train has been detected.

8. A hump locomotive movement control system as defined in claim 7 in which said third control means is further operable for actuating the transmission of a signal combination corresponding to a stop speed command for cancelling control of said speed control means by said receiving means.

9. A hump locomotive movement control system as defined in claim 8 in which said third control means comprises,

a. an automatic operation control means operable for establishing the wayside control condition necessary to transfer control of the hump locomotive speed control means to the associated receiving means,

b. a speed range selector device for selecting a signal combination corresponding to the initial signal and subsequently other signal combinations corresponding to the plurality of speed ranges for the hump locomotive,

c. a registry stick relay controlled by said automatic control means, said selector device, and said first and second control means for registering the establishment of said control condition when jointly said initial signal is selected, said first and second control means occupy cooperating positions, and said automatic operation control means is operated to establish said control condition,

1. said stick relay retaining said condition registry while said speed selector device continues to occupy any speed selection position,

d. control circuit connections to said transmitting means jointly controlled by said speed selector device and said stick relay for actuating the transmission of the selected signal combinations only when said control condition is established and registered.

10. A hump locomotive movement control system as defined in claim 9, in which said third control means also includes

a. a temporary stop register relay controlled by said first control means and said condition registry stick relay for registering operation of said first control means out of its cooperating position when a wayside control condition has been registered to briefly halt the hump locomotive,

b. a stick circuit for said temporary stop register relay completed by said first control means in its cooperating position and said condition registry relay in its nonregistering position,

c. a signaling circuit means controlled by said temporary stop registry relay in its registering position and said first control means in its cooperating position,

d. said signaling circuit means connected for actuating when completed another transmission of an initial request signal combination, thereby reestablishing the wayside control condition registry and reactivating control of the hump locomotive speed control means by the associated receiving means.

11. A hump locomotive movement control system as defined in claim 10 in which, said signal combinations transmitted by said transmitting means comprise a basic carrier signal modulated by a selected combination of tones.

Description

BACKGROUND AND OBJECTS

Our invention relates to a cab signal and speed control arrangement for railroad locomotives. More particularly, our invention is concerned with an arrangement for use in railroad classification yards for establishing cab signal indications in switching locomotives during their operation in the humping track leads and for remotely controlling an automatic speed arrangement for such locomotives during their use in the humping operations.

As the degree of automation of the operation of railroad classification yards is increased, the speed at which the cuts of cars are pushed over the hump in such yards becomes more critical. Humping speed, for example, must be such as to provide sufficient separation between successive cuts of cars rolling down the hump to allow for proper operation of the automatic switching system in routing the cars. In other words, it is desirable to avoid catchup between successive cuts of cars moving from the hump so that switches can be operated between their passage to prepare their separate routes and thus prevent misrouting the following cut of cars. In general, to achieve the optimum economy and efficiency in the operation of an automated classification yard, it is necessary that the humping speed be continuously adjusted to the existing circumstances affecting the movement of the cuts of cars being pushed over the hump. The use of a wayside hump signal and of cab signals on the locomotive to achieve proper humping speed is known. Such signals may be controlled by the hump conductor located near the crest of the hump to direct the speed of humping in accordance with the cut or switching list available to him. It has been found, however, that the locomotive engineer can not normally respond quickly enough to changes in the signal indications to manually control the speed of the humping locomotive to adequately satisfy the demands. The various locomotive builders can provide speed control apparatus for installation on locomotives which will respond to discrete, closely spaced (speedwise) but different speed commands to automatically vary the locomotive's speed quickly and accurately. The transmission of such different speed commands to the locomotive can then result in an accurate yet variable speed control as the humping operation may require to meet varying conditions such as successive cuts following similar routes over much of their travel, longer cuts which require additional time to reach free-rolling speed, and slow rolling cars. Such a speed control system, however, must not require the transmission of too many different signals to the locomotive. It must also allow the assignment of any one of several yard switching locomotives to humping duties. Finally, such a speed control system must provide a high safety factor which prevents duplicate reception of identical controls by two locomotives or the transmission of controls for opposing movements.

Accordingly, an object of our invention is a remotely operated automatic speed control system for humping locomotives in railroad classification yards.

ANother object of our invention is a remotely controlled arrangement for establishing and maintaining a selected speed for a humping locomotive in a railroad classification yard.

A further object of the invention is a system for transmitting speed selections to a locomotive in a railroad classification yard to maintain an optimum humping speed for the cars being released into the storage tracks of the yard.

It is also an object of our invention to provide a cab signal and speed control system for a plurality of switching locomotives in a railroad classification yard, any one of which may be used as the humping locomotive.

Still another object of the invention is a locomotive speed control system for railroad classification yards by which the speed of any selected one, of a plurality of switching locomotives, may be remotely controlled while assigned to provide motive power for humping operations.

Yet another object of the invention is a signal and speed control system for humping locomotives in railroad classification yards whereby the cab signal of the locomotive is controlled during the approach to the hump and the speed of the locomotive is remotely controlled during the actual humping operations.

A further object of this invention is an automatic speed control arrangement for humping locomotives in classification yards which is remotely controlled from a position off the locomotive in accordance with the cut release speed requirements of the humping operation.

It is also an object of the invention to provide, within a humping locomotive speed control system for classification yards, an arrangement for temporarily stopping the humping locomotive to permit special actions, e.g. pin pulling to uncouple a cut, without requiring the reestablishment of the automatic speed control already in operation.

Other objects, features, and advantages of our invention will become apparent from the following specification when taken in connection with the accompanying drawings and the appended claims.

SUMMARY OF THE INVENTION

Our inventive arrangement is based on classification yard cab signaling systems whereby two or more locomotives may receive cab signal indications transmitted to them from a remote control location. These cab signals and the added speed control of our arrangement provide a movement order transmission system only and do not carry route availability and safety information as does a main line cab signaling system. In other words, the system transmits orders to the engineer and/or locomotive control equipment to move the locomotive and the train in a specific direction and at a relative speed level. The orders do not, however, assure that the route is absolutely safe for the train movement although there is a general check against opposing movements on the humping track. The signal transmission system provides a single carrier current signal which is modulated by selected tones which carry the signal or speed command intelligence. Each locomotive of the several is assigned a different group of tones for the control of its cab signal and speeds. The modulated carrier current transmission is specifically shown herein as a space radio arrangement. It will be obvious, however, that other known transmission means may be used, for example, an inductive arrangement in which the principal channel is a wayside line wire. Also, although the tones are shown as being generated by audio frequency oscillators, the arrangement is not limited to the audio frequency range, but higher frequency tones may be modulated upon the basic carrier current in any manner well-known in the art.

The basic control of the arrangement embodying our invention is from the humpmaster control panel from which overall control of the classification yard operations is exercised. The arrangement further adds a supplemental control of the cab signals, on the locomotive selected for the actual humping movement, to the hump conductor whose control panel is located in the vicinity of the hump crest where he supervises the separation of the train into desired cuts, i.e., the so-called pin-pulling operation. The hump conductor also supervises and/or controls the route selection for the cuts being released from the hump. In most modern classification yards, the actual route selection is done by a digital computer which controls the classification operations, and possibly all vehicle movements within an even larger part of the terminal area. The route selection and cut list is prepared in accordance with the train consist recorded in the computer storages during or even before that train's arrival in the terminal. However, the hump conductor is still responsible to add, delete, or change route selections as necessary as the train is humped and assumes complete control of manually entering route storages if the computer becomes inoperative. The cab signal control exercised by this individual repeats the indications of the wayside hump signal and is directed by the same means on his control panel. Such control of the humping operations is given to the hump conductor through the selection, by the humpmaster on his control panel, of a specific locomotive to provide the humping motive power. As the leading end of the train being classified nears the hump, the humpmaster may assume control of the locomotive speed itself. Under these circumstances, the control of the locomotive is taken from the engineer on the locomotive and established on the humpmaster control panel. A special cab signal indication is transmitted at this time to the hump locomotive by the humpmaster. When its reception is acknowledged by the engineer by the performance on his part of specified actions to shift control, the automatic speed control circuitry is established for the remote control of the locomotive from the humpmaster's panel. This establishment of automatic speed control for the humping locomotive also removes control of the locomotive cab signal from the hump conductor, but requires his cooperation in setting his control panel signal lever to a predetermined position.

During the remote speed control for automatic operation of the locomotive, the discrete speed selection within a predetermined range is selected on the humpmaster panel. This speed selection is made in accordance with the length of the cuts being released, the separation of the cuts along their selected routes, that is, how far along the same route a cut follows the preceding cut before it diverts, and the relative rollability of the cuts of cars as known or estimated due to weather conditions. In taking into account all of these factors, the selected speed of the locomotive is varied from time to time as the particular factors differ. The locomotive engineer, however, retains the ability to resume local or emergency control to stop the train. Control is also returned immediately to him if communication between the wayside apparatus and the locomotive is lost, that is, the carrier current signal and the tone modulation is not received. Final synchronization of the system must always be from the remote location under the local control of the locomotive engineer under all conditions. An element of control is also retained by the hump conductor in order to temporarily stop the movement of the humping locomotive if needed to uncouple a particular cut, that is, if there is trouble with pulling the coupler pins between cars. The hump conductor can also enforce an emergency stop if conditions known only to him arise which require such action. A final alternate arrangement exists in that, although humpmaster remote control of the speed is shown specifically herein, the remote control of the automatic speed apparatus of the locomotive may be from a digital computer supplied to control route selection and switching, retarder operation, and other car or locomotive movements, during which the computer is also monitoring the car tracking and other supervisory functions. Such control is only conventionally shown, but is within the state of the art to be inserted into the speed control arrangement supplied by our invention.

DETAILED DESCRIPTION OF THE ILLUSTRATED SYSTEM

We shall now describe the details and operation of one specific embodiment of our invention as shown in connection with the system illustrated in the accompanying drawings in which:

FIG. 1 is a general diagrammatic showing of the system embodying our invention using conventional blocks and schematic control connections.

FIGS. 2, 3, and 4, when arranged as shown in FIG. 6, provide a schematic circuit diagram of specific wayside control circuits for one form of the system shown generally in FIG. 1.

FIG. 5 is a similar schematic circuit illustration of the locomotive apparatus associated with the wayside arrangement shown in the other figures.

FIG. 6 is a chart showing the arrangement of FIGS. 2, 3, and 4 necessary to provide proper circuit connections between the parts of the apparatus.

In the various drawing figures, similar reference characters designate similar parts of the apparatus. The wayside apparatus shown in FIGS. 2, 3, and 4 is provided with a source of energy for the operation of relays and for energizing various carrier transmitters and tone oscillators. This source of energy is not specifically shown but is assumed to be a direct current source of any known type having the proper capacity and voltage. Connections to its positive and negative terminals are shown in the circuit diagram by the references B and N, respectively. For some of the control panel indication lamps, a special flashing indication is provided by a particular positive energy terminal designated FB. This indicates a connection to the regular positive terminal B over a continuously coding contact so that periodic pulses of direct current energy are supplied thereto. The locomotive apparatus of FIG. 5 is also provided with a direct current source for which the terminals are also indicated by the references B and N. However, on the locomotive, a second source of energy which may be direct or alternating current is supplied for the signal lamps. The terminals of this source are indicated by the reference characters EB and EN. Actually, the two sources may be a single source of direct current energy with the proper voltage taps as required for correct illumination of the signal lamps and the energization of the various relays and other apparatus.

In all of the drawings, relay windings or coils are shown by conventional symbols. In general, contacts controlled by each relay winding are shown above or below the coil symbol and in vertical line therewith. Each movable armature element moves in an upward direction to close front contacts when the associated coil is energized. When the relay winding is deenergized and the relay releases, the armature elements move into the lower position to close against back contacts. However, for circuit drawing convenience and in order to simplify the illustrations, some relay contacts are separated from the corresponding relay winding symbol in the wayside circuit drawings. Such contacts are designated by the relay reference character and by a lower case contact reference. Such contacts, although separated in the illustration from the control winding, operate simultaneously with other contacts of that relay shown associated with the winding symbol. Each relay is designated by a reference character which will be explained hereinafter. Each relay contact is designated by a lower case letter reference character which is unique within the contacts associated with that relay only. Where a relay has special operating characteristics, specifically slow release or pickup characteristics, the contacts of such relays are marked with an arrow drawn through the movable armature and pointed to indicate the direction of slow action. For example, with a downward pointing arrow, slow release action is designated and such relays hold their front contacts closed for a predetermined period after the relay winding has become deenergized. At the end of such periods, the contact armatures release to close back contacts.

Referring now to FIG. 1, the general showing therein of the system embodying our invention provides a correlation between parts of the arrangement shown in greater detail in the other drawing figures. Across the top of FIG. 1 is a single line representation of the humping track lead of a railroad classification yard. Trains being humped, that is, classified, approach from the left through the insulated track section HAT, pushed by a hump locomotive illustrated conventionally in dot-dash outline and designated as Locomotive No. 1. This locomotive is one of two or more switching locomotives used in the yard or terminal area. Each is provided with cab signaling and speed control apparatus that is shown in detail in FIG. 5 and will be discussed specifically in connection with that drawing. Cuts of cars are pushed over the hump crest, illustrated conventionally, and released, descend through the master retarder, and are routed through group switches, shown in single line representation, onto selected storage track group leads illustrated as fanning out from the single hump lead. As is known in the art, the cuts move (off the drawing) through group retarders positioned along such track group and leads and thereafter move into selected storage tracks. The control of the speed of the cars in the retarders and the automatic switching to route the cars to selected tracks is not part of the invention disclosed herein and is mentioned only as a general background for the illustrated arrangement.

An insulated track section HAT is shown located in the hump lead in the immediate approach to the hump crest. Track section HAT is provided with a train detection track circuit in a well-known manner and herein illustrated only by the track relay HATR conventionally connected to the track section rails by a dotted line. Any well-known type of track circuit may be used. Briefly, the operation is such that relay HATR is energized and thus picked up when section HAT is not occupied by any part of a train. The relay releases when a train occupies the track section, thus detecting the immediate approach of such train to the hump crest. The hump signal HG and a trim signal TG are illustrated as being mounted on the same signal mast at the crest of the hump. The signal HG is faced so as to show the indications displayed thereon to the engineer on humping locomotives proceeding towards the hump crest. Signal TG is faced in the opposite direction so as to supply its indications to switching locomotives working in the storage tracks of the classification yards and providing trimming service therein. Such trimming operation locomotives may approach the hump crest in the reverse direction in connection with the work assigned. The hump conductor, whose control panel is shown by conventional block in the center of FIG. 1, is located in the vicinity of the hump crest in an area where the cuts of cars are uncoupled for release into the classification yard. This is the location at which the "pin-puller" functions, uncoupling the cars or pulling the pins as it is conventionally defined. The humpmaster and his control panel are located in a position normally at a higher elevation in a tower where he may oversee and supervise the entire classification operation.

Signal HG is controlled solely by the hump conductor, as indicated by the conventional dotted line connection, except for the hump slow control automatically applied when relay HATR releases as the train being humped occupies track section HAT. The conductor follows the release of relay HATR by similarly positioning his control lever to coordinate the system operation as will be fully explained later. Signal TG is controlled by the humpmaster, also as shown by the conventional dotted line, with the controls for signals HG and TG being interlocked to prevent simultaneous opposing moves over the hump.

The hump conductor also controls the cab signals in the hump locomotive when automatic speed control has not been established, as represented by the released condition of automatic control relay LASC (later defined), and when the humping locomotive cab signal channel selector is positioned for such control, as represented by the signal channel relay symbol CG whose details are shown in FIG. 3 and discussed later. As illustrated in the schematic circuits of FIG. 1, the cab signal control function selected by the hump conductor is transmitted from his panel over a back contact of relay LASC, the No. 1 locomotive channel selector on relay CG in its H (hump) position, and thence over a control mode selector switch for the No. 1 locomotive in the SA (semiautomatic) position to the cab signal selector and transmitter apparatus shown by a conventional block. The selected cab signal function is then transmitted by a modulated carrier current transmission, represented by a space radio channel, to the locomotive selected for the humping operation, here Locomotive No. 1. As will become apparent later, the circuit arrangement here represented by the single relay symbols CG is actually a group of signal channel relays which are controlled by the humpmaster to assign switching locomotives to humping operation. At the same time, cab signal control for other locomotives within the yard may be transmitted from the humpmaster control panel, in parallel channels here represented by the conventional connections over the No. 2 selector of relay CG in its Y (yard) position, to the cab signal selector and transmitter apparatus and thence over the same carrier current space radio channel by which controls are transmitted uniquely to the desired locomotive.

The automatic operation of the locomotive is illustrated as being controlled only from the humpmaster's panel. Relay LASC is energized to establish such control of the humping locomotive. Circuit interlocks are provided, as will be explained, to assure proper conditions, that is, trim signal TG not cleared, hump conductor controls in the hump slow position, section HAT occupied. The speed controls, in the form of a discrete selection of the desired speed range, are transmitted from the humpmaster panel over connections shown conventionally and including a front contact of relay LASC, the No. 1 locomotive channel selector or relay CG in the H position, and the control mode selector No. 1 in its SA position to the selector and transmitter unit. The same type of a modulated carrier signal is transmitted to the locomotive to effect the speed control, a selection of the tones singly or in various combinations distinguishing between the selected speeds.

An alternate method of such speed control of the hump locomotive may be from a digital computer controlling the classification yard and/or terminal operations in general, as was previously briefly mentioned. To illustrate this, control mode selector switches are illustrated in FIG. 1, each having an automatic or A position and a semiautomatic or SA position. When in use, the computer will determine the proper humping speed in accordance with the various factors previously discussed which would be registered or indicated in the computer storages. The computer will then actuate the transmission of the proper speed control signals. Relay LASC is energized as before, controlled by the humpmaster to establish the automatic operation, and then the specific control is transferred to the computer unit. A general system of terminal movement control is shown in the copending U.S. Pat. application Ser. No. 830,767 filed June 5, 1969, by Crawford E. Staples for Vehicle Movement Control System for Railroad Terminals. Although this copending application does not show the specific system here described, the computer control arrangement disclosed therein could be assigned the additional duty of hump locomotive speed control.

Referring to FIG. 5, we shall now describe in detail the locomotive carried apparatus involved in the system of our invention. The modulated carrier signal is received by the carrier receiver shown in the upper center of FIG. 5. This received carrier signal is demodulated and the received tone or tones applied to the corresponding tone receiver units, each tuned to a single tone. The carrier and tone receivers are shown by conventional blocks, since any one of several known types may be used. The only requirement is that they be compatible with the wayside units shown in FIG. 3. Upon reception of its corresponding tone signal, each tone receiver energizes the associated tone register relay R. Each locomotive has a group of three tones assigned thereto for transmitting the specific cab signal or speed command to the locomotive. The tone receivers on each locomotive are uniquely tuned each to receive one of the tones assigned to that particular locomotive. Since this apparatus in FIG. 5 is assumed to be that for Locomotive No. 1, to which the three tones A, B, and C are assigned, the tone receivers are tuned for these tones and the register relays are designated as AR BR, and CR.

In FIG. 5, the cab signal for the locomotive is indicated at the left by the dot-dash block which encloses the symbols of the cab signal lamps. It is illustrated as a light type signal in which the illuminated lamp displays the effective cab signal indication. These lamps in the cab signal are designated as HF, HS, BU, and STOP. The cab signal command displayed by the last lamp, when illuminated, is obvious. The other lamps, when illuminated, display a hump fast, hump slow, or back up signal indication, respectively. If it is further desired, the signal indications may also have selected color aspects with hump fast being green, hump slow--yellow, back up--white, and STOP--RED. An alternate choice provides a flashing red aspect for the back up indication and a steady red for a stop indication, both provided by the same lamp unit. For convenience, the color designations are not used herein and separate lamp units are used for each of the cab signal indications. The fifth lamp, enclosed in an adjacent dot-dash block and designated as lamp AO, indicates when illuminated that the locomotive is in remote, automatic speed control operation, as will be shortly explained.

Below the cab signal lamps is the acknowledgement pushbutton ACKPB, used by the locomotive engineer for acknowledging an automatic operation request signal received from the humpmaster location. This device, as shown by the standard symbol used, is a spring return pushbutton in which the single, normally open contact is closed only when the pushbutton is actuated. When the actuating pressure is removed, the contact once again opens. In other words, pushbutton ACKPB closes the circuit through its contact only when actuated. Also for operation by the locomotive engineer is a mode selection lever shown within the automatic speed control apparatus block at the lower left of FIG. 5. This is illustrated as a two-position lever having a manual position M and an automatic position A. This lever is provided with three contacts, closed only in the A position, to supply a designated energy over the wire leads connected to the normally open fixed contacts. This conventional illustration of the locomotive operating mode selection designates a two-position lever which remains in the last-operated position, so that when placed in the A position, the lever contacts remain closed after its actuation until it is restored to the manual position. This single mode selection lever as illustrated represents the various operations required of the locomotive engineer prior to acknowledging an automatic speed operation request. Depending upon the specific locomotive control system supplied by the manufacturer, this includes such actions as placing the throttle in the No. 1 position, releasing the brake handle, assuring that the dynamic braking is off, and/or other similar actions. For convenience, we have chosen to show only a single lever having the three normally open contacts which are closed by the simple operation of the lever into its automatic position A.

The terminals shown on the right side of the automatic speed control apparatus block represent the speed selections in effect when the speed control energy from contact c of the mode selection lever is applied to a particular terminal. The numerical designations of the terminals represent the miles per hour speed range selection which will be enforced by the speed control apparatus. The speed control energy source is entirely a matter within the control apparatus of the locomotive and, except for its application to the proper terminal, bears no part in the inventive concept of the arrangement provided by our system. The pushbutton ACKPB, the mode selection lever, and the indication lamp AO are mounted on the locomotive control panel while the cab signal lamps are mounted so as to be in full view of the locomotive engineer.

As already indicated, the control system of the invention is based on the use of a carrier current signal modulated by one or a combination of three tone signals to select a cab signal indication or to designate a particular speed control command. One representative arrangement of the tones is shown in the following table in which the presence of a tone is designated by the digit 1 and the absence of a tone by the digit 0. ---------------------------------------------------------------------------

Tones Cab Signal Indication Automatic Mode A B C Manual Mode Automatic Speed Selection mode in m.p.h. __________________________________________________________________________ 1 0 HF HS 1.75 0 1 0 HS HS 1.50 0 0 1 BU HS 1.25 0 0 0 STOP STOP (STOP) 1 1 1 HS (flashing) HS 1.00 1 0 1 HS 2.00 1 1 0 HS 2.25 0 1 1 HS 2.50 __________________________________________________________________________

basically, the locomotive equipment controls the cab signal lamps. In the at-rest condition of the apparatus or system, with no tones being received on the locomotive, the STOP lamp in the cab signal is energized. This circuit may be traced from terminal EB of the lamp energy source over back contacts a, in series, of each of the relays AR, BR, and CR and through the filament of the STOP lamp to terminal EN. The stop relay S is also energized under these conditions, its winding being connected in multiple with the filament of the STOP lamp. This relay must be of a type that will respond to the type of energy provided by the lamp source EB-EN. The hump fast lamp HF is energized when the single tone A is received on the locomotive, the circuit including front contact a of relay AR, the lamp filament, and back contacts b, in series, of relays ALA and ALR, which will be defined shortly in connection with the automatic operation of the locomotive.

When a single tone B is received, the circuit for the hump slow lamp HS is completed and extends from terminal EB at back contact a of relay Ar, over front contact a or relay BR, back contacts c, in series, of relays ALR and ALA, and the filament of the lamp to terminal EN. Similarly, when the single tone C is received, the circuit for backup lamp BU is completed between terminals EB and EN and includes back contacts a of relays AR and BR, front contact a of relay CR, the filament of the lamp, and back contacts b of relays ALA and ALR.

The automatic operation lamp AO has a simple circuit including its own filament and front contact e of relay ALA. The conditions which close this circuit will be defined shortly. Other circuits are completed at special times for lamp HS. One such circuit includes front contact c of relay ALA for steadily energizing the lamp HS during automatic operation. Another circuit for lamp HS extends from terminal EB at coding contact a of the flasher relay FL and includes front contact c of relay ALR and back contact c of relay ALA. Relay FL is of the well-known flasher or coding-type relay so that, when energized continuously operates its contact a between the closed and open positions. This coding operation under the energized condition or relay FL is indicated by the dotted line in the upper position of the movable armature of its contact a. Such relays are well known in the art and any one of several known types may be used for this purpose. The coding operation of its contact a is continuous, periodically opening and closing the circuit for lamp HS, when relay FL is energized.

Turning now to the portion of the locomotive apparatus which becomes active for establishing automatic operation of the locomotive from the humpmaster position, the first relay which is actuated is the automatic locomotive registry relay ALR. This relay, together with relay FL, becomes energized upon the simultaneous reception of all three tones by the locomotive apparatus, which is the initial request signal for automatic locomotive operation. The circuit for energizing these relays extends from terminal B over front contacts b, in series, of relays CR, BR, and AR, back contacts d of relay ALA, and the windings of relays ALR and FL in parallel to terminal N. Each relay is energized, relay ALR picks up, and relay FL begins operating. With front contact c of relay ALR now closed, lamp HS immediately displays a flashing indication due to the coding action of contact a of relay FL.

The closing of front contact a of relay ALR completes a stick circuit for this relay and for coding relay FL, extending from terminal B at back contact c of relay S, which is released at this time with tones being received, and further including back contact d of relay ALA. This stick circuit holds relays ALR and FL energized if the engineer's acknowledging action next described is delayed beyond the duration of the transmission of the three tone initial request signal. The pickup of relay ALR also prepares a circuit for energizing the automatic locomotive acknowledgement relay ALA when the locomotive engineer takes his acknowledging action in response to the flashing indication. The circuit for relay ALA, in addition to its own winding, includes front contact d of relay ALR, the normally open contact of pushbutton ACKPB, back contact b of the automatic stop relay AS, and contact b of the mode selection lever in the speed control apparatus. Obviously relay ALA is energized when the mode selection lever has been moved to its automatic A position and the locomotive engineer further acknowledges the receipt of the automatic operation request by activating pushbutton ACKPB to close its normally open contact. Relay ALA, upon energization, picks up to close its own front contact a which completes a stick circuit bypassing front contact d of relay ALR and the contact of pushbutton ACKPB. Once energized, relay ALA thus remains energized as long as relay AS remains released and the mode selection lever remains in its A position.

The automatic locomotive memory relay ALM has a simple energizing circuit including front contact f of relay ALA and its own winding. This relay is thus energized and picks up whenever relay ALA is energized and closes its front contact f. Relay ALM has a stick circuit including its own front contact a and back contact b of stop relay S and thus remains energized once automatic operation is initiated until a stop indication is received on the locomotive. Automatic stop relay AS has an energizing circuit including front contact a of relay S and front contact b of relay ALM. The stick circuit for relay AS includes its own front contact a and winding and contact a of the mode selection lever in the speed control apparatus which is closed, of course, when the lever is in its A position. Thus, when automatic operation is in effect and a stop indication of any sort is received on the locomotive so that relay S picks up, relay AS is energized and then holds energized until action is taken by the locomotive engineer to move the mode selection lever out of its A position. The open back contact b of relay AS, under this condition, prevents the reenergization of relay ALA until some action is taken by the locomotive engineer in response to the stop indication. It is to be noted that relay ALM also controls a second energizing circuit for relays ALR and FL. This circuit includes back contact c of relay S, front contact c of relay ALM, and back contact d of relay ALA. The utility of this circuit is best explained later during the operational description.

The above signal and speed command chart indicates which speed commands are selected under various conditions of tone reception during automatic operation. Circuits for controlling these speed selections include contacts of the three tone receiver relays. For example, the initial automatic operation request command of all three tones is converted, after acknowledgement, into the lowest speed selection command of 1.0 m.p.h. The circuit extends from the speed control energy source over contact c of the mode selection lever, front contact c of relay BR, front contact d of relay AR, and front contact e of relay CR to the 1.0-mile-per-hour terminal on the automatic speed control apparatus. Another typical circuit may be traced, under the conditions of tones A and C received, in which the speed selection command is made over contact c of the mode selection lever, back contact c of relay BR, front contact c of relay AR, and front contact c of relay CR to the 2.0 terminal of the speed control apparatus. Other speed selection circuits may be traced as desired by reference to the above chart and the circuit drawing. It should be noted particularly that an absence of all tones under the automatic operation condition, so that back contacts c of relays BR and AR and back contact d of relay CR are all three simultaneously closed, supplies the speed control energy to the STOP terminal of the speed control apparatus which enforces an emergency stop of the locomotive.

Referring to FIGS. 2, 3 and 4, assembled as shown in the chart of FIG. 6, we shall now describe the wayside circuits and apparatus as mounted on the various control panels indicated in FIG. 1, and as contained in various equipment cabinets and boxes at the wayside locations. At the left of FIGS. 2 and 3 are shown the control levers for manually initiating various actions. The hump signal lever HGL, shown in the upper left of FIG. 2, is mounted on the hump conductor's panel which, as previously mentioned, is located in the vicinity of the hump crest. This lever is used to control the hump signal HG and at times the cab signal is assigned humping locomotive. A single indication lamp is shown associated with this lever, the hump slow indication lamp HSK, which repeats in part the hump slow positioning of the hump signal lever HGL, that is, the lever positioned in its S position. This lamp also repeats the hump slow indication displayed on the hump signal and generally in the cab signal of the humping locomotive. Other indication lamps are actually provided to repeat other signal indications for the hump conductor but are not shown since they are not critical to the arrangement of our invention and the use of such indication lamps is conventional.

The hump control lever shown at the left center of FIG. 2, which is a two-position lever having a stop and a clear position, is mounted on the retarder operator control panel which is not shown in FIG. 1. This lever is positioned in its clear position when the retarders are ready for operation and further indicates that the classification yard is prepared to receive cars over the hump, or for other actions within the yard. This lever position is repeated in the control apparatus of our invention by the hump clear repeater relay HCP which is energized by a circuit from terminal B over the hump control lever in its clear position, a contact POAP, and the winding of relay HCP of terminal N. Contact POAP is a conventional showing of various checks made throughout the wayside apparatus and for this reason it is enclosed in a dot-dash rectangle to indicate its external location. This contact specifically repeats both a power-off indicator, which causes the contact to be closed as long as power is available for operating the various retarder controls and other apparatus, and an air pressure indicator which also causes the contact to be closed when sufficient air pressure is available for operating the retarders, when of the electropneumatic type, and the switch machines of the electropneumatic type. Thus contact POAP when closed indicates that power is available to control the yard apparatus and that the air pressure is sufficient as required to operate the various types of apparatus. Thus, the energized position of relay HCP is a safety check providing coordination to avoid the inadvertent humping of cars when the classification yard is closed or is not operating condition due to lack of electrical energy or fluid power, particularly for the retarders and switch machines. For the rest of the description that follows, we shall assume that relay HCP remains energized since the purpose of this safety check is obvious and need not be incorporated in the detailed description.

The remaining levers shown in FIG. 2 and all of those shown in FIG. 3 are mounted on the humpmaster control panel. These comprise a two-position trim signal lever TGL, a two-position master signal control lever MGL, a two-bank, four-position, cab signal control lever for each switching locomotive that may be assigned to humping operation, or that is provided with cab signals, and a multiposition hump locomotive channel selector lever HCS. EAch of these levers will be more fully discussed hereinafter in the description but it may be said that the hump locomotive channel selector lever HCS is used to assign a particular locomotive in the yard to humping operations and for transferring the control of the cab signal of this particular locomotive to the hump conductor. Since it is assumed herein that two locomotives are assigned to the yard for which the apparatus is designed, the lever HCS shown in FIG. 3 thus has an off or 0 position, a first and second position, one for each of the locomotives, and in addition a wayside or W position in which control of the wayside signals only, that is, the hump signal HG, is assigned to the hump conductor. Since only two locomotives as assumed herein, two locomotive cab signal control levers, one for Locomotive No. 1 and the other for the Locomotive No. 2, are required so that cab signal control for each locomotive operating in the yard may be exercised from the humpmaster panel, when such control is desired.

Two other levers, shown in the upper left of FIG. 4, are mounted on the humpmaster control panel. One is a two-position hump locomotive automatic control lever, which is normally in its OFF position but, when automatic operation is desired is moved to the ON position. In this latter position, this hump locomotive automatic control lever is directly repeated by the locomotive automatic control relay LAC, the energizing circuit for which is obvious. The final lever on the humpmaster control panel is the multiposition, hump locomotive speed selector HLSS. This lever device has an OFF position and seven speed selection positions which are designated by numerical references corresponding to the speed selections available in the automatic speed control apparatus on the locomotive, as shown in FIG. 5. The control arm of this lever overlaps between the contacts of the speed selection positions in order, as will be fully understood later, to retain continuous transmission of at least one of the tone signals while remote automatic speed control of the hump locomotive is in effect. In connection with all of the operating levers herein discussed, the sequence of the terminals on the multiposition levers may in actual practice be in a different order than that specifically shown, or alternatively, provision may be made to move the lever contact arm in the multiposition levers from an existing position to any other position without contact with the intervening terminals, in order to make more convenient certain control actions which will be described. However, such options are not critical to the operation of the system and the following description will assume that the multiterminals of the various levers are located as shown.

Returning now to the master signal control lever MGL shown in the lower left of FIG. 2, this lever is repeated by the master signal register relay MGR and the master signal register stick relay MGRS. It should be noted that lever MGL is normally retained in its clear position by the humpmaster and is moved to the stop position only when exceptional circumstances require the halting of yard operations. Under normal conditions then, the circuit is completed from terminal B over the lever arm and the clear position contact and front contact b of relay MGRS through the winding of relay MGR to terminal N. Relay MGRS is normally energized by its stick circuit which includes front contact a of relay mgr and front contact a and the winding of relay MGRS. This latter relay also has a pickup circuit including back contact a of relay MGR and front contacts c, in series, of the stop repeater relays 2SP and 1SP which are associated with the cab signal control levers on the master panel. It may be briefly explained that each relay SP is in its picked-up position if the associated cab signal control lever has been at the stop position and the locomotive corresponding to that lever has not since been assigned to hump conductor control. Contacts of relay MGR are included in various circuits for controlling cab signals and locomotive operation as will be developed in the following discussion. It provides a cross-check that yard operation is authorized before various signal or speed commands may be exercised. Relay MGRS, of course, provides a check, before the pickup of relay MGR after lever MGL has been moved to the stop position, that the locomotive cab signal controls have been moved to the stop position by the humpmaster and that he has not assigned these locomotives to other control positions prior to the time of reclearing the yard for operation. During the remainder of this specification, it is assumed that the master signal control lever MGL remains in its clear position and that relay MGR thus remains picked up with its front contacts closed.

The signal lamps for signals HG and TG, shown conventionally in FIG. 1, are illustrated at the right of FIG. 2, The designations of the lamps of signal HG, except for the T-lamp at the bottom, have the same meaning as already defined for the cab signal lamps of FIG. 5. Again the hump signal lamps may be colored for better sighting by the locomotive engineer and would generally, reading from the top, provide green, yellow, white and red aspects. The trimming signal TG lamps are designated as STOP, which may be a red aspect, and T, the clear or trimming authority signal, which may be a green aspect. The T-lamp at the bottom of the HG signal pointing in the opposite direction from the TG-signal provides a display to the hump locomotive engineer and the hump conductor that the trimming signal is clear and thus that humping operations are prohibited. This particular signal lens may be clear with a superimposed letter T to designate the aspect being displayed.

The signal TG indication is controlled by the trim signal relay TH. For example, when this relay is released, the stop lamp of signal TG is energized over back contact a of relay TH, connections being between terminals B and N of the source. It is to be understood, of course, that the lamps of both these signals may be energized by alternating current of a low voltage if so desired, but for convenience the normal direct current terminals are shown. When the relay TH is energized so that its front contact a is closed, energy is supplied in parallel to the lamps T in both signal TG and signal HG to provide authority for a trimming operation by a switching locomotive working in the classification yard itself. Such authority also extends to movements up onto the hump in the reverse direction if necessary for the work required.

Relay TH is controlled by the trim signal lever TGL which is operated by the humpmaster. Lever TGL is normally in its stop position so that energy is supplied from terminal B over the lever arm in this position and front contact a of relay HCP to a trim lever stop repeater relay TLSP. Relay TLSP is also provided with a stick circuit including its own front contact a and front contact a of relay HCP in the pickup circuit. This repeater relay is thus normally energized as long as the trim signal lever TGL has been in its stop position and the hump control lever remains in its clear position subsequently so that yard operations may continue. The circuit for relay TH extends from terminal B over the lever TGL operating arm in its clear position, back contact a of relay LAC, to check that automatic operation is not in effect, front contact b of relay TLSP, front contact b of time element stick relay TES, and the winding of relay TH to terminal N. It is obvious that relay TH cannot be energized and trim signal TG cleared unless relay TLSP is picked up which is, of course, an indication that the classification yard is prepared for train movements. For trimming operations, this particularly involves the availability of power and air pressure for the operation of switches necessary for the trimming movements. Signals TG may thus be placed to STOP semiautomatically if relay TH releases due to the successive release of relays HCP and TLSP, e.g., if a low air condition occurs and contact POAP opens. After this happens, signal lever TGL must be returned to its STOP position before signal TG can again be cleared. Relay TH also requires that the time element stick relay be energized, which is an indication and cross-check, as will become apparent later, that the hump slow aspect is not displayed on humping signal HG. As will be explained, this hump slow aspect is normally not displayed until the train to be humped has at least reached track section hat in the immediate approach to the hump crest. This relay TES contact check in the circuit for relay TH is thus an indication of whether or not there is a train immediately approaching the hump which will be releasing cars against the possible movement of the trimming locomotive.

We shall now describe the selection of a particular locomotive for humping operations and the assignment of its control to the hump conductor. As previously explained, the specific arrangement shown in FIGS. 2, 3, and 4 assumes only two locomotives working in the yard and provided with signal and control apparatus. Obviously more locomotives may be used within the yard, each one of which may be provided with corresponding cab signal apparatus. Under the assumed conditions, therefore, the hump locomotive channel selection HCS has only four positions. One of these is an off position 0 in which no assignment is made for hump conductor control. The fourth position W assigns only the control of the wayside signal HG to the hump conductor but, as will appear later, also prohibits any remote speed control of the hump locomotive during such a condition. The other two numerically designated positions, as will become apparent, assign to the humping operation and control by the hump conductor the correspondingly numbered locomotive.

When lever HCS is placed in the W-position, a circuit is completed for the wayside signal control relay WSG which extends from terminal B over the contact arm of lever HCS in its W-position, back contacts b, in series, or relays 2CG and 1CG, and the winding of relay WSG to terminal N. This energizing circuit has cross-checks over back contacts of the other two signal channel relays to assure that control of a particular humping locomotive has not already been assigned to the hump conductor. Relay WSG has a stick circuit including its own front contact a and, in multiple, front contacts b of the hump signal relays HD, HH, and HBU, to be described. Thus, once it is picked up, relay WSG remains energized and held up as long as any one of the movement indication aspects of signal HG is being displayed, as will be more fully described shortly. As will also become apparent, when relay WSG is picked up so that its back contacts d, e, and f are open, any control of the humping locomotive cab signal by the hump conductor is interrupted. Automatic operation of that locomotive under speed selection control by the humpmaster is also interrupted. Thus, selection of relay WSG establishes wayside signal control only of that particular humping operation.

When lever HCS is placed in its No. 1 position, a circuit is completed over the contact arm in this position, further including back contact c of relay 2CG and back contact b of relay WSG, for energizing the No. 1 cab signal channel relay 1CG. This circuit, of course, checks the released position of the other two signal channel relays in the selector circuit arrangement. With lever HCS in the No. 2 position, a circuit is completed including back contacts c of relays 1CG and WSG for energizing the No. 2 cab signal channel relay 2CG. Again, these back contacts check that neither of the other two relays of the group is already energized prior to the selection of relay 2CG. Each of the CG relays is provided with a stick circuit including, of course, its own front contact a and front contacts b, in multiple, of corresponding signal tone control relays C which are energized to actuate the various audio oscillators, as will be discussed shortly, For example, the stick circuit for relay 2CG includes front contacts b of relays 2HFC, 2HSC, and 2HBUC which are associated with the audio tone oscillators D, E, and F which supply commands and signals to the No. 2 locomotive, as will be more fully explained.

When either switching locomotive herein assumed is working in the yard and is not assigned to humping operations, that is, its cab signal channel is not selected for control by the hump conductor, such cab signal control remains with the humpmaster who is provided on his panel with a control lever for each locomotive cab signal. Each of these cab signal control levers has four positions and is provided with two contact banks or levels. Referring to the No. 1 locomotive cab signal control lever in the upper left of FIG. 3, its contact arm is shown in its normal condition, that is, the stop position. A circuit is completed only over the contact arm of the second or lower contact level when the lever is so positioned. The other three contact positions, designated F, S, and BU, are respectively, for the hump fast, hump slow, and backup cab signal indications. When the cab signal control lever is in any one of these three movement aspect positions, control circuits are established for the tone control relays C, which have been previously briefly mentioned.

Referring to the No. 1 locomotive control lever, when in its usual or normal stop position, a circuit is completed over the lower contact arm and back contact g of relay 1CG for energizing a No. 1 stop repeater relay 1SP. This relay is provided with a stick circuit including back contact g of relay 1CG, its own front contact a and front contact b of relay MGR. Thus relay 1SP holds energized as long as the No. 1 locomotive is not assigned by the humpmaster to humping operations and its cab signal channel control given to the hump conductor, as would be indicated by the pickup of relay 1CG to open its back contact g. With relays 1SP and MGR both picked up, a circuit is completed from terminal B over front contact c of relay MGR and front contact b of relay 1SP to apply this energy to the upper level contact arm of the No. 1 locomotive cab signal control lever. It is thus apparent that, at any time that control of the No. 1 locomotive cab signal is to be restored to the humpmaster's panel and relay 1CG has released, the cab signal control lever must be placed in its STOP position, to reenergize replay 1SP before its control of the C relays is effective. This prevents the inadvertent display of any improper cab signal indication immediately upon restoration of humpmaster control of the locomotive.

If this lever then is moved to its F position, energy is applied over the contact arm, the F terminal, and back contact d of relay 1CG to relay 1HFC, which is the hump fast tone control relay for the No. 1 locomotive. Again, this control circuit is completed if the No. 1 locomotive has not been assigned to the hump conductor. When such an assignment is made, so that relay 1CG picks up and closes its front contact d, control of relay 1HFC is shifted to control by the hump conductor signal lever or to control by the automatic locomotive operation arrangement, each of which controls will later be more fully described. Similar circuits exist for the No. 1 hump slow tone control relay 1HSC and the No. 1 hump backup tone control relay 1HBUC over other back contacts e and f, respectively, of relay 1CG and the upper contact arm of the No. 1 locomotive cab signal control lever in its S or BU position, respcetively. Control of relays 1HSC and 1HBUC likewise shifted to the hump conductor or to the automatic control apparatus when relay 1CG is picked up by assignment of the corresponding locomotive to humping operations. Similar circuits for relays 2SP, 2HFC, and 2HBUC over contacts of the No. 2 locomotive cab signal control lever may be traced, if desired, but are obvious from the drawings when reference is made to the immediately preceding description of the corresponding No. 1 relays. Again, control of these latter mentioned relays for the No. 2 locomotive is shifted to hump conductor control or automatic locomotive control when relay 2CG picks up upon selection of the No. 2 locomotive for humping operations.

At the right of FIG. 3 are shown the tone oscillators and the carrier current transmitter for transmitting the cab signal or speed commands to the locomotives. The audio oscillator for tone A is activated by a circuit from terminal B including front contact a of relay 1HFC, the connection to terminal N of the source being permanent from the other input terminal of the oscillator. Similar circuits for the tone B and tone C oscillators include front contact a of relays 1HSC and 1HBUC, respectively. The output of each oscillator, when activated, is applied through a tone amplifier, if needed, to the carrier current transmitter to modulate the signal carrier output of this transmitter prior to its transmission to the locomotive receiver. The tone oscillators, the amplifier, and the transmitter apparatus are shown by conventional blocks since such apparatus and its operation is well known and any one of several standard types of each may be used in this arrangement without affecting the overall operation of the system. Further, although audio oscillators are indicated specifically, it has already been mentioned that the tones need not be in the audio range but may be selected to be of higher frequency range. Similar activating control circuits for tone oscillators D, E, and F are provided over front contacts a of relays 2HFC, 2HSC, and 2HBUC, respectively. Tones A, B, and C are assigned to the No. 1 locomotive while tones D, E and F are assigned to the No. 2 locomotive in the specific arrangement shown. One or more of each group of tones may be active and transmitted over the modulated carrier current simultaneously. Each will be received only by the proper locomotive apparatus and decoded as previously discussed in connection with the description of the apparatus of FIG. 5.

The hump conductor control of the hump signal HG and at times of the cab signals of the locomotive specifically assigned to humping operations is exercised through the hump signal lever HGL. This is a four-position lever, each position being designated in a manner similar to that previously discussed for the cab signal control levers on the humpmaster panel. In other words, position F is for the hump fast indication, position S, hump slow, and position BU for the backup indication, while the STOP position obviously controls a stop indication on the signals involved. Operation of lever HGL is effective only if at least the wayside signal control has been assigned to the hump conductor by the humpmaster through his hump locomotive channel selector. When this action is taken by the humpmaster and a locomotive is assigned with lever HGL in its STOP position, the hump lever stop repeater relay HLSP is energized. The circuit is traced from terminal B over lever HGL operating arm in the stop position, front contact h of relay 1CG, 2CG, or WSG, which contacts are connected in parallel but only one closed at a time, back contact b of relay LASCSP, which will be defined later, back contact a of hump approach register relay HHR, back contact b of time element relay TE in parallel with back contact c of hump approach signal relay HH, front contact b of relay HCP, a normally closed contact CFP, front contact F of relay MGR, and the winding of relay HLSP to terminal N. Contact CFP, which is included in the same dot-dash rectangle as the previously defined contact POAP, is a normally closed contact which opens in response to any failure of the computer used in the overall yard control system. It serves then as a check that operation should be halted until a duplicate standby computer can be brought into service. It is assumed herein, for convenience, that contact CFP remains closed since such computer operation is not specifically a part of the inventive concept.

When relay HLSP, thus energized, picks up, it completes a stick circuit in which its own front contact a replaces the operating arm of lever HGL in the just traced energizing circuit. The stick circuit does have alternate paths which are at times effective. In addition to the multiple paths over contacts h of the CG or WSG relays, front contact m of the locomotive automatic stick control relay LASC is in multiple with back contact b of its repeater relay LASCSP. An alternate path bypassing back contact a of relay HHR includes the corresponding front contact and front contact d of relay HH. Either front contact c of hump clear signal relay HD or of hump backup signal relay HBU, which contacts are connected in multiple, may replace the path over front contact b of relay HCP and contact CFP. It is to be noted that relay HLSP is provided with slow release characteristics, as indicated by the downward pointing arrows through its contact armatures, so that the closure of its front contacts will be maintained to bridge brief interruptions in the stick circuits as alternate paths are connected to replace existing paths. However, similar to relay TLSP, if relay HLSP becomes deenergized automatically because contact CFP or contact POAP opens (the latter acting through contact b of relay HCP), lever HGL must be returned to its STOP position to reenergize relay HLSP and thus to reclear signal HG.

We shall now discuss the control of the various hump signal relays such as the hump clear signal relay HD, the hump approach signal relay HH, and the hump backup signal relay HBU. Also involved will be the control of the hump approach register relay HHR. Assuming that the hump conductor places his lever HGL in the F position, a circuit is completed over the lever arm from terminal B, further including front contact a of track relay HATR, front contact b of relay HLSP, and the winding of relay HD to terminal N. Energy is also supplied from the connection at the left terminal of the relay winding to wire connection 13. The purpose of this energy will be discussed later in connection with locomotive cab signal control. When relay HD picks up, it completes a circuit for energizing the hump fast lamp HF of signal HG. This circuit includes back contact a of relay HH, front contact a of relay HD, and the filament of the signal lamp. As will be apparent later, the hump fast signal aspect is only displayed when the train to be humped is still some distance from the crest of the hump and to conserve time may be moved forward at a relatively rapid speed.

It is to be noted that with lever HGL in its F-position, when the train occupies section HAT so that relay HATR releases, the track relay back contact repeater relay HATBP is energized over back contact a of relay HATR with energy supplied over terminal F of lever HGL. At the same time, the opening of front contact a of relay HATR deenergizes relay HD which releases. The closing of front contact a of relay HATBP completes a simple circuit for energizing the hump approach register relay HHR. This relay is also energized with lever HGL in its S-position over a straight forward circuit. Relay HHR picks up to close its front contact b which completes a circuit for energizing the approach signal relay HH providing that relay HLSP is energized, so that its front contact c is closed, and relay TH is released, closing its back contact b. Back contact b of relay TH is included to provide an interlock circuit of check that the trim signal has not been cleared for operations in the classification yard by a switching locomotive which thereby would have authority to approach the hump from the reverse direction. This is necessary since relay HH is normally energized only when a train being humped has closely approached the hump crest so that humping operations are about to begin. It is to be noted that an opposing movement check over a back contact of relay TH is not necessary in the circuit for relay HD since this relay is energized and the hump fast indication displayed only when the train is at some distance from the hump crest, so that a trimming locomotive operating on the reverse side of the hump does not present a dangerous situation. The closing of front contact a of relay HH when it picks up completes the simple circuit circuit for energizing the hump slow indication lamp HS in signal HG. Lamp HF has, of course, been deenergized and become dark with the release of relay HD. The application of energy to the winding of relay HH also applies similar energy to wire lead 12 which is connected at the left-hand terminal of the winding of relay HH.

The remaining position of lever HGL, that is, the BU position, energizes backup signal relay HBU, the circuit also including front contact d of relay HLSP. Energy is also applied by this circuit to wire lead 11 which is similar in use to the leads 12 and 13 previously mentioned. It may be noted at this point that when lever HGL is moved out of its F-position to either the S- or the BU-position, energy is removed from the winding of relay HATBP which immediately releases, thus leaving only the circuit over terminal S of the lever for energizing relay HHR. Thus relay HHR and correspondingly relay HH can not remain energized when relay HBU is energized by signal lever HGL. With back contacts a of relays HH and HD closed, the closing of front contact a of relay HBU energizes signal limp BU, thus causing signal HG to display a backup indication.

When relay HHR was energized and picked up, the closing of its front contact c completes circuit for supplying energy to the hump slow indication lamp HSK associated with lever HGL. With relay HATBP picked up, coded positive energy is supplied to lamp HSK over front contact c of this relay from terminal FB, which was previously explained. However, when signal lever HGL is moved out of the F-position, the closing of back contact c of relay HATBP supplies steady energy from terminal B to the indication lamp. The opening of back contact e of relay HH interrupts the stick circuit for the time element stick relay TES, which circuit further includes only front contact a of the relay itself. When relay TES releases, the closing of its back contact a prepares a circuit for energizing time element relay TE when relay HH again releases to close its back contact e. Time element relay TE is of the slow pickup type, such relays being known in the art, so that when its winding is energized it does not respond to close its front contacts until a predetermined time period has passed. This time period may vary from a few seconds to several minutes, if desired, but is preset to have a constant value in any one installation. When relay TE does close front contact a, it immediately completes an energizing circuit for relay TES which further includes the previously mentioned back contact e of relay HH. Relay TES immediately picks up and opens its back contact a to deenergize relay TE, completing at the same time its own stick circuit over the corresponding front contact a. When deenergized, relay TE releases in a relatively short time although some delay is connected therewith. The full release of relay TE to close its back contact b is required to maintain the stick circuit for relay HLSP when relay HH opens its back contact c.

Referring now to FIG. 4, we shall describe the apparatus connected directly with the remote operation of the automatic speed control of the locomotive. Such automatic operation of the humping locomotive is initiated by placing the hump locomotive automatic control lever in its ON position to energize locomotive automatic control relay LAC. At the same time, selector lever HLSS is placed in its first speed selection position, that is, the 1.0-mile-per-hour-speed terminal position. Energy from terminal B over the contact arm of lever HLSS, when in the 1.0 position, flows in parallel circuits through the diode matrix, actually the upper diode in each group of four, to simultaneously energize the tone relays AT, BT, and CT. Each of these relays has a capacitor-resistor time delay snub connected in multiple with its winding in order to retard slightly the release of these relays when their windings are deenergized. Such arrangements are used when the desired slow release period is of a short nature and is more easily obtained with winding snubs than by using relays having inherent slow release characteristics.

With each of the tone relays picked up, a circuit is completed for energizing the locomotive automatic stick control relay LASC. This circuit is traced from terminal B at either front contact k of relay ICG or front contact k of relay 2CG in the lower right of FIG. 4, only one of which will be closed, continuing over back contact g of relay WSG, front contacts c, in parallel, of relays AT, BT, and CT, front contact f of relay HH, back contact b of relay HATR, back contact b of relay HATBP, front contact b of relay LAC, front contacts b, in series, of relays CT, BT, and AT, and the winding of relay LASC to terminal N. This circuit checks that at least one of the two locomotives has been assigned to humping operation and to the control of the hump conductor, that the wayside only signal control condition has not been established, and the the hump slow indication is being displayed by signal HG and, as will appear later, by the cab signal of the locomotive itself. It also checks that the train to be humped is already occupying the approach track section HAT but that the track repeater relay is deenergized, indicating that lever HGL is not in its hump fast position. Actually, with relay HATBP released, lever HGL must be in its S position for relay HH to be energized. This circuit also checks that automatic control has been selected, as indicated by the energized condition of relay LAC, and that lever HLSS is in its lowest speed selection position so that all tone relays are energized.

Relay LASC, thus energized, picks up, closing its own front contact a to establish a stick circuit which bypasses the series contacts of the tone relays and front contact b of relay LAC. The closing of front contact b of relay LASC completes an obvious circuit for energizing its stick repeater relay LASCSP, which picks up to close its own front contact a, thus completing a stick circuit over front contact e of relay HLSP. Relay LASCSP thus remains energized over its stick circuit while relay HLSP is picked up, which provides a number of circuit checks for the continued energization of this stick repeater as was discussed in connection with the circuits for relay HLSP. Relay LASC closes its front contact c when energized to supply energy to indication lamp LAK so that the lamp is steadily lighted to indicate that automatic control of the locomotive speed is now in effect, or at least is requested. Lamp LAK has a second energizing circuit including front contact c of the temporary stop relay TST, energy being supplied over this circuit from terminal FB so that if front contact c of relay LASC is open, the lamp is supplied with coded energy to provide a flashing indication which, as will become apparent, is an indication of the temporary stop condition.

Only one other relay now remains to be fully defined and described, the temporary stop relay TST just mentioned above. The purpose of this relay will appear in detail later but it is used in connection with briefly halting the automatically operated locomotive for special uncoupling purposes on the hump. The energizing circuit for relay TST extends from terminal B at back contact d of relay HHR over front contact c of relay LAC, front contact f of relay LASC, and the winding of relay TST to terminal N. A first stick circuit for this relay includes back contact d of relay HHR and front contact c of relay LAC, and thence includes front contact a of relay TST and back contacts d of relays HD and HBU. When relay HHR picks up, a second stick circuit is immediately completed for relay TST which includes front contact d of relay HHR, back contacts d, in parallel, of relays CT, BT, AT, and LASC, front contact b of relay TST, and diode D2, thence over back contacts d of relays HD and HBU to the winding of the relay. Diode D2 prevents a sneak circuit between the first and second stick circuits which would supply energy over front contact d of relay TST, as will be next described, before relay HHR picks up. With relay HHR picked up to close its front contact d and front contact d of relay TST also closed, a circuit is completed, further including diode D1, to apply energy to the parallel circuits through the basic diode matrix to briefly energize each of the tone relays CT, BT, and AT.

OPERATIONAL DESCRIPTION

We shall now describe the operation of the system embodying our invention under specific but typical conditions occuring in a classification yard. It is assumed that both locomotives operating in this yard are under control by the humpmaster. Cab signal control is exercised by the operation of the cab signal control levers in the humpmaster panel which are shown specifically at the left of FIG. 3. Tones A, B, and C are transmitted to Locomotive No. 1 while tones D, E, and F are selectively transmitted to Locomotive No. 2 to control the cab signal indications displayed in the locomotive cabs as such control is appropriate for the assigned work of the locomotives. There will be occasions, of course, when the specific work assigned such locomotives in the whole classification yard or terminal area is inappropriate for control by cab signal indications from the humpmaster panel. Such operations are in addition to that period of time when the cab signal is controlled by the hump conductor, as will be shortly described. If any of the work of these locomotives during this period includes work in trimming the actual storage tracks of the classification yard, such movement will be further authorized by the clearing of signal TG through operation of lever TGL by the humpmaster.

It is now assumed that a train already arrived in the terminal is ready for classification and that the humpmaster selects locomotive No. 1 to provide the power for movement of this train over the hump for release into the selected storage tracks. In accordance with this decision, the humpmaster places the hump locomotive channel selector HCS in the No. 1 position. This completes the necessary circuit for energizing relay 1CG so that it picks up and closes its front contact a to prepare for the eventual closing of its stick circuit which includes, in parallel, front contacts b of relays 1HFC, 1HSC, and 1HBUC. This stick circuit network will be completed for holding relay 1CG energized only when the hump conductor initiates his control of the locomotive cab signal but from that time on will prevent the inadvertent assignment of another hump Locomotive, e.g., No. 2, to the hump conductor's control. In other words, once Locomotive No. 1 is assigned to the hump conductor and he assumes control of its cab signal indications, relay 1CG is held energized by the stick circuit network and thus control cannot be taken away from the hump conductor during the humping operation except for the purpose of remote automatic operation of the locomotive speed.

Upon pickup of relay 1CG, with lever HGL in its STOP position, relay HLSP is energized and picks up, its circuit network having been previously discussed. At this time, specifically, the circuit includes front contact h of relay 1CG and back contact b of relay LASCSP. The circuit further includes at least back contact b of relay TE, front contact b of relay HCP, and contact CFP. When relay HLSP picks up to close its own front contact a, this completes the stick circuit with that contact replacing the contact arm of lever HGL in the network. Establishment of the control of the No. 1 locomotive in the hump conductor's panel is now completed.

To expedite the movement of the train to the hump, lever HGL is now placed in its F position. Relay HD is thus energized, since relay HATR is picked up and relay HLSP has picked up to close its front contact b. This also applies energy to wire 13. Tracing this wire lead connection from FIG. 2 to FIG. 3, the circuit further includes back contact k of relay LASC, back contact f of relay WSG, and front contact d of relay 1CG to the winding of relay 1HFC. This latter relay is thus energized and picks up. The closing of front contact a of relay HD energizes lamp HF of signal HG on the wayside while the closing of front contact a of relay 1HFC completes the circuit for energizing the tone A oscillator. The output of the tone A oscillator modulates the carrier signal being generated by the carrier transmitter from which it is transmitted to the selected locomotive. On Locomotive No. 1, as shown in FIG. 5, the reception of the tone A signal energizes relay AR, and this in turn energizes the lamp HF of the cab signal unit. Thus the wayside signal HG is displaying a hump fast indication and likewise the cab signal on Locomotive No. 1 is displaying a similar indication. The locomotive engineer is thus authorized to move the train, with the locomotive actually on the rear pushing, toward the hump at the hump fast speed range. It should be noted that signal TG may still be cleared for trimming work in the actual storage tracks of the classification yard by the other locomotive since there is no interlocking check in the circuit for relay TH by which the energizing of relay HD prevents the clearing of this signal. For purposes of the subsequent description it is assumed, however, that relay TH is not energized and is in its released position so that signal TG is displaying a stop indication.

When the leading car of the train being humped occupies section HAT in the hump approach, relay HATR releases and completes a circuit for relay HATBP which picks up since lever HGL is in its F position. Relays HD and 1HFC are released at this time since energy is removed from the winding of relay HD and from wire 13. This darkens the hump fast lamp in the wayside signal HG and eventually on the locomotive due to the absence of tone A reception. The closing of front contact a of relay HATB energizes relay HHR, however, and this in turn completes a circuit for relay HH and applies energy to wire connection 12. Tracing wire 12 to FIG. 3, a circuit is completed over back contact h of relay LASC, back contact e of relay WSG, and front contact e of relay 1CG to the winding of relay 1HSC. This latter relay picks up and applies energy to the tone B oscillator which, thus activated, applies its output to modulate the carrier signal being transmitted to the locomotive. Reception of tone B on the locomotive energizes relay BR so that, when relay AR releases, a circuit is completed over front contact a of relay BR to energize lamp HS of the cab signal. This gives the locomotive engineer a hump slow indication which directs him to slow the speed of the train and also indicates to him that the leading car has entered track section HAT. Also, the wayside signal HG indication is changed and lamp HS there is also energized to provide a similar indication.

With relay HHR picked up and relay HATBP also in its energized condition, a circuit is closed to provide coded energy to indication lamp HSK on the hump conductor's panel so that this lamp provides a flashing indication. This indicates to the hump conductor that his lever HGL is out of coordination with the existing signal aspects being displayed. He then moves the lever HGL operating arm to position S which holds relay HHR energized but deenergizes relay HATBP which then releases. Steady energy is now applied to indication lamp HSK and it is steadily illuminated to provide an indication that the hump slow signal aspect is being displayed under lever control.

The opening of back contact e of relay HH interrupts the stick circuit for relay TES, as previously explained, and this relay releases, opening its front contact b in the circuit for relay TH. This now prevents any clearing of the trim signal and thus provides a safety interlock between the control circuits. Relay HLSP is now energized over alternate paths of its stick circuit which include front contact a of relay HHR and front contact d of relay HH, and only back contact b of relay TE in the subsequent parallel paths since back contact c of relay HH is now open. Relay HLSP, of course, has sufficient slow release time that any brief interruption of its stick circuit during the transfer action of these various contacts will not allow the relay to release. It is to be noted that during the period relay HD was energized, its front contact c serves as an alternate path bypassing front contact b of relay HCP and the contact CFP. Thus, any interruption of this latter path of the stick circuit is bypassed and the train at least can continue to approach the hump until its leading edge occupies the approach track section HAT. Front contact c of relay HBU, if this relay were energized, would serve a similar purpose to allow the train to back away from the hump even through relay HCP might temporarily release due to some power failure or loss of sufficient air pressure.

With the train now in immediate approach to the hump, that is, occupying section HAT, the humpmaster elects to control the humping speed automatically from his control position in accordance with the cut list and other known conditions. In some yards, this remote control of the locomotive speed may alternately be given to the hump conductor or again alternately may be provided by the computer directing the movement operation throughout the terminal as is indicated in FIG. 1 and as discussed in connection with that general showing. Herein the remote speed control will be described as being exercised by the humpmaster from his control panel. In order to allow this remote, automatic speed control, the hump conductor places or retains his signal control lever HGL in the S position. Thus, relays HHR and HH remain picked up and the HS lamp in signal HG remains illuminated. The humpmaster then places the hump locomotive automatic control lever into its ON position and selector HLSS into into the 1.0 position. Relay LAC and all of the tone relays CT, BT, and AT are energized and pick up. Subsequently as a result of these actions, relay LASC is energized and picks up, completing its own stick circuit. Relay LASCSP is also energized by the closing of front contact b of relay LASC and picks up, completing its stick circuit including front contact e of relay HLSP. This latter relay remains energized since its stick circuit is already completed over the alternate path over front contact m of relay LASC when back contact b of relay LASCSP opens. Lamp LAK is also steadily energized over front contact c of relay LASC and thus illuminated to provide the locomotive automatic indication.

When relay LASC picks up, the control of relays 1HFC, 1HSC, and 1HBUC is transferred from wire leads 11, 12, and 13 to leads 14, 15, and 16, which extend between FIGS. 4 and 3, by the closing of front contacts g, h, and k of relay LASC. With relays AT, BT, and CT picked up at this time, energy from terminal B at front contact e of relay LASC is connected over front contacts a of the three tone relays to leads 14, 15 and 16, and thence over the just-mentioned front contacts of relays LASC and back contacts d, e, and f of relay WSG to relays 1HFC, 1HSC and 1HBUC over front contacts d, e, and f of relay 1CG. With each of the three 1-C relays thus energized and picked up, the closing of front contacts a of these relays energizes all three audio tone oscillators A, B, and C, so that these three tones are simultaneously transmitted to the No. 1 locomotive.

The reception of the three tones by the corresponding receivers on the locomotive, shown in FIG. 5, activates relays AR BR, and CR so that they pick up. As previously described, the closing of front contacts b of these three relays in the series circuit energizes relays ALR and FL. These relays are retained energized by their stick circuit, previously traced and originating at back contact c of relay S, so that relay ALR remains picked up and relay FL continues its coding operation if, prior to the engineer's acknowledgement, the transmission of the three-tone signal is halted by the movement of lever HLSS to a higher speed selection. Lamp HS in the cab signal, which was previously lighted under control of hump signal lever HGL in its S-position, is now energized by coded energy over contact a of relay FL, the circuit further including front contact c of relay ALR and back contact c of relay ALA. This indicates to the locomotive engineer that automatic control of his locomotive speed is requested by the humpmaster. Unless some local condition prohibits transfer, the engineer places the mode selector in its A position, closing the three normally open contacts a, b, and c responsive to the movement of this lever, and then actuates pushbutton ACKPB which completes the circuit for energizing relay ALA. It is to be noted that contact b of the mode selection lever must be closed when the pushbutton is actuated in order to complete the energizing circuit for this relay and that front contact a of relay ALR must also be closed. When relay ALA picks up, it closes its own front contact a to complete the stick circuit which bypasses contact a of relay ALR and the contact of the pushbutton in the pickup circuit. Relay ALM then is energized and picks up, closing its front contact a to complete the stick circuit further including back contact b of relay S.

When relay ALA picks up, it also closes its front contact c to transfer lamp HS of the cab signal to steady energization so that this lamp remains steadily lighted during automatic speed control operations. In addition, lamp AO on the control panel is energized over front contact e of relay ALA. These two lamps indicate to the engineer that automatic operation of his locomotive is now in effect. With all of the tone relays R picked up, speed control energy is applied over contact c of the mode selection lever, and over front contact c of relay BR, front contact d of relay AR, and front contact e of relay CR, to the 1.0 mile-per-hour speed control terminal. The automatic speed control apparatus then functions in accordance with its design to control the locomotive speed to this selected range. It should also be noted that, at this time, the connection from cab signal lamps HF and BU to terminal EN of the lamp energy source is interrupted at back contact b of relay ALA. This connection was first interrupted at back contact b of relay ALR when the automatic operation request signal was received. The interruption is maintained as just described, relays ALR and FL having released since they are deenergized by the opening of back contact d of relay ALA upon acknowledgement of the automatic operation request by the engineer. Obviously, of course, the control of lamp HS is now disconnected from contact a of relay BR by the opening of back contact c of relay ALA.

The humpmaster now manipulates selector HLSS in order to select different speeds for the humping operation. These speed selections are made in accordance with information obtained from the cut list as to the separation of the routes for successive cuts of cars, the length of the various cuts, his estimate as to the possible retarder release speed in accordance with the track fullness of the assigned storage tracks, and the rollability of the various cuts of cars, if known, or at least as estimated in accordance with the weather condition effect existing at that time. It is to be noted that each of the tone relays AT, BT, and CT, as previously described, is provided with an R-C snub in multiple with its winding to provide a retardation period for the release of these relays when deenergized. This is necessary in order that the three tones are simultaneously transmitted for a sufficient period to assure response by the locomotive receivers in the event that the humpmaster should quickly move selector HLSS to a higher speed selection. The stick circuit for relay ALR then provides time for the engineer to take the various acknowledgement actions necessary. Relay LASC, of course, is held energized over its stick circuit which includes front contacts, c, in multiple, of the three tones relays. Since the selector lever HLSS contact arm overlaps between the speed selection terminal positions, one or more T-relays are always picked up and there is no loss of energy in this stick circuit. Further, at least one tone is always being transmitted so that there is no complete loss of tone reception under normal operations by the receivers on the locomotive. The various tone combinations are transmitted as selectively controlled by the T-relays which are energized through the diode matrix between the speed selection terminals of lever HLSS and the windings of the tone relays. This results in wire leads 14, 15, and 16 being energized in corresponding combinations so that relays 1HFC, 1HSC and 1BHUC repeat the position of the tone relays T.

On board the locomotive, the energized combinations of relays AR, BR, and CR, which correspond to the transmitted tones, apply speed control energy to the speed terminals of the speed control apparatus over a contact matrix of these three relays in the selected manner to obtain the different speeds. Upon completion of the humping of that particular train, the return of the control of the locomotive to the engineer is accomplished in a simple manner by the humpmaster restoring lever HLSS to its OFF position and the hump locomotive automatic control lever to its OFF position to release relay LAC. When the engineer has restored the mode selector to the M position, control of the hump locomotive movement is returned to the hump conductor who can then direct by cab signal and wayside signal, through the backup signal aspect, that the locomotive return in the reverse direction or direct whatever other movement is desired. It is to be noted that, since the relays release in the order LASC, HLSP, LASCSP, lever HGL must first be returned to its stop position, to reenergize relay HLSP, prior to the selection of any wayside or cab signal indication to direct the further movement of the locomotive.

During automatic operation, the humpmaster can always halt the movement of the train toward the hump by moving selector lever HLSS to its OFF position. This removes the transmission of all tones and the locomotive apparatus, in the absence of reception of any tone, selects the stop terminal in the speed control apparatus for application of speed control energy. The loss of reception of all tones by the locomotive through any communication system fault also stops the train in a similar fashion. It is to be noted that normally an installation of this type will include standby tone oscillators and carrier transmitters in the wayside equipment. These are not shown in the specific illustration herein since the use of standby communication or transmission equipment in such systems is conventional and changeover systems are well known and any desired arrangement may be used. The train-carried communication apparatus will normally not be duplicated due to the extra expense but this is a matter of choice by the user of the system.

If the humping locomotive is halted for any external cause, the locomotive engineer initially will take no action. The removal of all of the tones and the resulting release of all of the tone receiver relays R energizes relay S, as well as the STOP lamp in the cab signal. The pickup of relay S energizes relay AS, since relay ALM is still picked up to close its front contact b. Relay AS completes a stick circuit over the mode selection lever contact a which is still closed as long as the engineer takes no action. Back contact b of relay AS opens to interrupt the stick circuit for relay ALA which then releases and cancels the existing automatic operation condition. This releases also deenergizes lamps HS and AO and deenergizes relay ALM, since relay S is picked up and its back contact b is open to interrupt the stick circuit for relay ALM. To restore the automatic operation condition after such a stop action, the humpmaster again transmits the request, that is, all tones simultaneously, by placing lever HLSS in the 1.0 terminal position. The locomotive engineer must move the mode selection lever to position M, then return it to the A position, and once again acknowledge by actuating pushbutton ACKPB. These actions release relay AS to prepare the circuit for relay ALA at back contact b of relay AS. The renewed request causes lamp HS to flash and the locomotive engineer then knows that he may actuate the pushbutton to acknowledge and reestablish the automatic condition.

If, during automatic operation, any condition arises or is discovered on the locomotive or train or along the track which requires the train to be stopped or some other action to be taken locally, the engineer takes over the operation of the locomotive by restoring the mode selection to the manual mode. This may be the result of the operation of the brake valve to stop the train or the opening of the throttle beyond the No. 1 position in order to hold the train on the hump grade because of insufficient speed by the automatic control. This effective movement of the mode selection lever to its M position opens the contact b to interrupt the stick circuit for relay ALA which releases. This extinguishes lamp AO and the steady energization of lamp HS. The resulting illumination of any other cab signal lamp because of the tone combination being received is ignored by the engineer since for other reasons he had already taken more restrictive local action varying from the selected speed. In addition, the opening of contact c of the mode selection lever removes speed control energy from the speed terminals of the control apparatus so that further automatic control of the speed is not presently possible. However, relay S is not now energized, since at least one tone signal is being received, the humpmaster having taken no action to move selector HLSS from its existing position. Relay ALM thus remains energized over its stick circuit. The second energizing circuit for relays ALR and FL is then completed over back contact c of relay S, front contact c of relay ALM, and back contact d of relay ALA when this last relay releases. Relay ALR picks up and completes its stick circuit. Relay FL begins operating and again supplies coded energy to lamp HS, over front contact c of relay ALR and back contact c of relay ALA. The flashing indication on lamp HS is then a reminder to the engineer that automatic operation is still desired by the humpmaster and should be restored when possible. To restore automatic operation after such a local control action, the engineer restores the mode selection lever to the automatic A position and actuates pushbutton ACKPB. The transfer then from the local control of the locomotive to the automatic control is made as previously described for the initial request. It will be thus apparent that the locomotive engineer retains the final control of placing the locomotive in automatic operation, both when the condition is initially requested and to restore the automatic control after any interruption, whether it be because of local conditions requiring his intervention with local control or because of some stop condition arising externally in the communication system. In other words, synchronization of the system condition, especially in an emergency, rests with the locomotive apparatus once the synchronization has been initiated from the humpmaster position. This provides an additional safety factor in the system.

Another occurrence when the humpmaster need not take action in order to restore automatic operation after the humping train has been stopped is the temporary stop action which is specially taken in order to uncouple a cut of cars, that is, "pull a pin" in the trade terms, which is otherwise not possible, for various reasons, while the train is moving toward the hump. It will be apparent, however, that even in this case the locomotive engineer must still restore the automatic operation condition since, in his position at the far end of the humping train, any stop that is not the result of his actions is an external action which requires him to restore the automatic condition. A temporary stop action is controlled by the hump conductor who, on the spot near the crest of the hump supervising the uncoupling of the various cuts, will realize the need for stopping the train to obtain a particular uncoupling. The conductor moves his lever HGL from the existing S-position to the stop position to initiate this action. This releases relay HHR and in turn relay HH. Other relays not involved in the operation may also release but are not discussed here. The indication on wayside hump signal HG goes to STOP under his condition since all three signal relays will be in their released position. The humpmaster, however, need not move his speed selector HLSS from whatever speed selection condition exists. The opening of front contact f of relay HH interrupts the stick circuit for relay LASC which releases. However, the closing of back contact d of relay HHR completes the previously traced energizing circuit for relay TST prior to the release of relay LASC to open its front contact f, since relay HHR releases first. Relay TST picks up and sticks over its first stick circuit, previously traced, including its own front contact a and back contacts d of relays HD and HBU. The release of relay LASC also results in the deenergization of relays 1HFC, 1HSC, and 1HBUC, initially by opening its front contact e. This removes all energy from the tone oscillators so that that tone transmission ceases. This condition is assured since the release of relay LASC to close its back contacts g, h, and k, thus transferring the control of the tone control relays to leads 11, 12 and 13, has the same effect since there is no energy on these three leads at this time with signal lever HGL in its stop position. The halting of the transmission of all tones, of course, stops the locomotive since the R-relays release and select the stop speed terminal. With the stop indication being received on the locomotive so that relay S picks up, the previously mentioned action occurs in which relay AS picks up to interrupt the circuit for relay ALA which releases. Relay ALM also releases under this condition.

When the uncoupling is achieved, the hump conductor restores lever HGL to the S-position. This of course reenergizes relay HHR and in turn relay HH. However, it is to be noted that when relay LASC released to open its front contact m, relay HLSP was deenergized since its stick circuit is interrupted with back contact b of relay LASCSP also open. This latter relay is held by its stick circuit which includes front contact e of relay HSLP. Since lever relay HLG usually remains in its STOP position for a sufficient time exceeding the slow release period of relay HLSP, this relay will release which in turn will be followed by the release of relay LASCSP. The closing of back contact b of this latter relay, with lever HGL at stop, restores the pickup circuit for relay HLSP. Relay HLSP then picks up and sticks with its slow release period bridging the resultant later changeover of its stick circuit as relays HHR and HR are reenergized and pick up again. Of course, if relay HLSP does not release during this operation because it is of such short duration, the stick circuit will be restored when the following actions occur. The pickup of relay HHR to close its front contact d shifts the stick circuit for relay TST to the second stick circuit which includes, in multiple, back contacts d of the tone relays and of relay LASC. Also through front contact d of relay TST and diode D1, all of the tone relays are energized through the diode matrix. The closing of front contacts b and c of these tone relays reenergizes relay LASC which picks up and then completes its own stick circuit. This causes all three tones to again be simultaneously transmitted since the tone control relays are again reenergized over circuits including leads 14, 15 and 16. With all the T relays picked up, followed by the pick up of relay LASC, the second stick circuit for relay TST is interrupted and this relay, thus deenergized, releases. This removes energy from the circuit through diode D1. However, the slow release period of each tone relay T is sufficient so that the simultaneous transmission of the three tones lasts for a sufficient time that the locomotive apparatus may receive and respond thereto.

On the locomotive, simultaneous reception of all three tones restores the automatic operation request, that is, lamp HS begins flashing. The engineer then moves his mode selector lever to the manual position M and then back to its A position. This releases relay AS and prepares a circuit for energizing relay ALA again when the acknowledging pushbutton ACKPB is actuated. Thus, these actions by the locomotive engineer restore the automatic operation condition. Then shortly, when the release time of the tone relays has expired, only that relay combination which is energized over the existing position of selector HLSS will remain picked up and whatever previously existing tone combination was being transmitted will be restored and the humping speed again increased to that level. This action thus was under the control of the hump conductor with the cooperation of the locomotive engineer to restore the automatic condition on board the locomotive and no action by the humpmaster was necessary to change the speed selection already existing. It may be noted that lamp LAK provides a flashing indication, while relay TST is picked up with relay LASC released, to inform the humpmaster that a temporary stop action is occurring.

The system of our invention thus provides an improved cab signal and speed control system for the humping locomotives in railroad classification yards. When automatic speed control is established, it is remotely controlled by the humpmaster or others in accordance with the existing conditions so that an efficient and economical humping operation at the optimum speed is obtained. Safety checks are included in this system to protect not only the humping movement but any possible opposing movement necessary in the operation of the yard. A single control point for supervising the overall operation of the humping and classification yard operation is thus established, yet the actual control of the humping locomotive may be delegated, if desired, to various other locations and personnel. System synchronization requires the cooperation of both locations, that is, both the remote control location and the local control location onboard the locomotive, in order to establish the remote automatic operation of the locomotive. Under all conditions, however, the final control of the locomotive is retained by the locomotive engineer who must execute the final actions in order to establish automatic operation and who may restore his own local control under any emergency conditions. If automatic operation is halted for any reason, it can not be restored without the cooperation of the engineer, who has the on-the-spot knowledge of any existing conditions which require the nonestablishment of such automatic control. At the same time, an unacknowledged request for automatic operation appears as a continuing indication on the locomotive control panel, so that a lack of response by the engineer is a deliberate action for which he is accountable. Operations of classification yards are thus improved and a greater efficiency in a movement of cars through the yards is obtained.

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Current U.S. Class:	246/122R ; 246/182R; 340/12.22
Current International Class:	B61L 17/00 (20060101); B61L 3/00 (20060101); B61L 3/12 (20060101); B61L 003/00 ()
Field of Search:	246/182R,23,63,187,4,6 325/55,64