US2097624A - Automatic train stop system for railroads - Google Patents

Description

NOV 2, 1937. T. KITTREDGE ET AL 2,097,624

AUTOMATIC TRAIN STOP SYSTEM FOR RAILROADS Filed Feb. 17. 19:54 2 Sheets-Sheet 1 THEIR ATTORNEY.

Nov; 2, 1937. T KITTREDGE ET AL 2,097,624

AUTOMTIC TRAIN STOP SYSTEM FOR RAILROADS Filed Feb. 17, 1934 2 Sheets-Sheet 2 l FIGZ.

THEIR ATTORNEY.

distant relay DR, commonly o normal condition o tice;an d,-th a t a suitable form of trip stop,

Patented Nov. 2, 1937 UNITED STATES AUTOMATIC TRAIN sToP sxrsTEM'FoR` nAlLnoAps 1 Thomasinaredge, Rthe'rfqa, N.J., and Her-f bert D.

Brooks, OceansidagN. Y;,'assignors to General Railway Signal Company, Rochester,

i Application February 17, 1934, seriaiNo. 711,700 'y A' il claims. v (craieavr yThis invention relates to automatic train `stop systems or railroads, and more particularly to the control circuits for thevtrain stop oritrip .devices on' the track-commonly employed `insuch systems on'subwaysand thelike. 1 r One. object of this invention is toV provide; an improved organization of relays and control, cir-` cuits for electrically controlled trip stops, which will allow the clearing of the trip upon the en- 'trancehof atrain into the associated track section after a time interval determined bythe sequential operation of the home and distant relays commonly employed, in such a way that a longer time interval may be obtainedwiththe number i of relays ordinarily used than is possible .at present.

:Other objects, characteristic features, and advantageso the invention willbe in part apparent, and in part pointed but as the description progresses.

The accompanying drawings show in a simplified and diagrammatic manner oneembodiment of the invention as applied to one control location, Fig. l showing the parts and circuits inthe withno trains present, and Fig, 2 showing the parts and' circuits when theftrain stop is in the raised or stop'position, due to the presence of a train ahead.

In the embodiment of the invention illustrated, it is assumed that the trackway is dividedinto blocks such as A and B in the usual manner; that signals-of a suitable type, such as color-light signals S, arelocated at Athe entrance to each block and controlled in accordance withA the usual pracdesignated V andshown conventionally, will be located near the entrance to each block, a prede-- termined distance in advance of the insulated joints, this trip stop being of the welleknown type comprising `electrically controlled power mechanism for moving the trip arm from its raised or stopping position to a clear position against a spring or counter-weight, as 38, and maintained there. `In the form illustrated, this trip stop mechanism is assumed to be operated to the clear position by an electric moto-r M, through gearing or the like 40, and held infthat position by a hold-clear device W coacting with an armature 4I on the device V. This trip stop mechanism also vincludes a circuit controller, arranged to open and close contacts in different positions. This circuit controller is illustrated diagrammatically as comprising pivoted contactarms I to 5, movable through an angle of 90, and engaging arcuate segments or stationary contacts in diilerent positions of the trip arm.

The usual track relay T, home relay HR, and used in systems of this type, are shown diagrammatically and conventionally. The home and distant relays are assumed to be ofthe two-element. alternating current type, with local and line phase windings. Such relays operate their contacts only when both windings are energized.

`For the purpose of simplifying the drawings, the conventional symbols BX, NX, and CX are employed `to indicate connections to a transformer supplyingicurrent tothe various circuits, it being understood thatfBX and NX indicate vterminals having positive and negative instantaneous voltage `in relation to the terminal CX.

Fig. l illustrates ,the parts in the normal condition with no trainspresent.v The track relays T and IT of the blocksortrack sections A and B are both energized. The line phase Winding H of thenlinerelay HR is energized by a circuit readily traced -rom BX 55, through the front contact 6 oftrack relay IT, line wire front contact 3 of track relay T,.wires 9 and IQ, winding H, to CX. The` local Winding HQ of this relay is energized over theY same `line'circuit Vthrough wire II, front contact IZMoirelay HR, wires I3 and I4, winding HQ, to CX.

The local winding DQ of isdirectly energized; Vand the line phase winding Dis energized over the line circuit from NX 55, through front contact I5 of the line relay IHR for the block B, line wire I6, front contact Il of track relay T, wire I8, winding D, to CX.

The train stop V is held in the clear position. bythe energization of hold-clear W over a circuit from BX IIQ, front Contact of track relay T, wires 2I and 22, iront contact 23 of line relay wires 26 and 25, circuit controller contact 3 ofthe stop mechanism, closed in the clear position, Wire 26, hold-clear W, to VNX Ill).

Thus,l under normal clear conditions, with no train present, the line -relay HR and the distant relayvDR are both energized; and the train stop V is held in the clear position.

When a train enters block A under such clear conditions, the dropping of the track relay T establishes a retaining circuit for holding the trip stop in the clear positon, said circuit being from BX HG, back contact 2l) of track relay T, Wire the distant relay DR 2l, circuit controller contact l closed in the clear position, wires`28 and 28, hold clear W, to NX I I.

Considering new the case where there is a train ahead in the block B, as shown in Fig. 2, the presence of thistrain drops the track relay IT, opening its front contacts 6 and 81 to de-energize the line relays HR and IHR. The opening of theiront contact I5 of the line relay IHR deenergizes the distant relay DR. Thus, the signal S indicates stop, block overlapv characteristicof the trip stop system. The de-energization of the line relay HR opens its front contact 23 and thus de-energizes the hold clear W, so that the trip stop V assumes its stopping position,

there being the usual one vided it is travelling at a very low speed. This result is obtained by locating the trip stop VY a' short distance in advance of the'insulatedjoints,`

so that the train may travel a short distance, after dropping the track relay T, before Vencountering the trip stop, and by providing circuits for clearing the trip stop after a short interval of time, so that if the train consumes more than a predetermined time in travelling such predetermined distance, corresponding with a speed below the desired speed limit, the trip stop-will be clear by the time the train reaches it. 'Ihis time interval is measured in accordance With this invention by the sequential operation ofthe home and distant relays.v

VAssume now that a train enters the block A- under danger traine conditions Ywith a train ahead in the block B, as shown in Fig. 2. The dropping of the track relay T closes a circuit for energizing the distant relay DR, which may Vbe traced from BX 55, circuit controller contact I of the trip stop,V closed in the stop position, Wires 3i) and i3, back vcontact l2 of the line relay HR, wire 3l, back contact I1 of track relay T, wire I8, winding D to CX. This energization of the distant relay DR establishes a circuit for energizing the line phase Winding H of the home relay HR from'BX Ill), back Contact 20 of track relay T, Wires 2l and 32, Ycircuit controller contact of thetrip stop mechanism closed in the stop position, wire 373, front contact 34 of relay DR, wires 35 and l0, winding H, to CX. 'I'he local winding HQ of the home relay HR is directly energized through the circuit controller contact i of the stop mechanism.

When the home relay HR is thus energized, the closing of its front contact I2 provides-a circuit for energizing its line phase winding H through the circuit controller contact l. Also, the opening ofthe back contact l2 of the home relay HR de-energizes the distant relay DR, which closes its back Contact 36, so that a circuit for the motor M of the train stop mechanism is established from BX HQ, through the back Contact 36 of relay DR, wires 3l and 22, Vfront contact 23 of relay HR, wire 2, circuit controller contact 2 of the trip stop mechanism, Wire 39, motor M, to NX Il.

The trip stop mechanism now operates to the clear position, the circuit controller contacts l and 2 remaining closed' until the trip armv reaches the clear position and circuit controller contacts 3 and l are closed, whereupon the opening of contact i de-energizes the home relay HR, the opening of contact 2 de-energizes the motor M, and the closing ofcontact 4 establishes the retaining cir-cuit through the back contact 2D of the track relay T to hold the trip in the clear position.

It will be noted thatA the time interval between the dropping of the track relay T and the movement of the tripfstop V to the clear position is measured by time intervals required to energize distant relay DR, then energize the home relay VHR, then de-energize distant relay DR, then move the trip arm to the clear position. Inrother words, in addition to the usual `clearing time of theV trip stop mechanism, the organization of control circuits in accordance with this invention requires they sequentialpicking up of the,l distant and home relays, followed by the dropping of the `distant relay, thereby providing an additional time interval from the same relays commonly employed.

Various adaptations, additions, and modications, may be made in the particular construction and arrangement of parts shown and described, Without departing from the invention.

What we claim isz- 1. In an automatic stop system for railroads, in combination, an electrically controlled stop mechanism located a short distance beyond the entrance to a block having the usual track relay, a home relay and a distant relay, a clearing circuit for said stop mechanism including a front contact of the home relay and a back contact of the distant relay, and circuit means controlled by said track relay for picking up the distant relay and home relay in Succession, and then dropping the distant relay to establish said clearing circuit.

2. In an Yautomatic train stop system of the character described, a trip stop mechanism, a track relay, a home relay, and a distant relay, means controlled by said track relay and effective when thetrack relay is deenergized and the stop mechanism is in the stopping condition, to pick up the distant relay through a circuit controlled by the home relay for actuating said stop mechanism to the clear position, after a time interval measured by the picking up of thedistant relay and home relay in succession, and the dropping of the distant relay.

3. An automatic'train stop for railroads, com.

prising, in combination, an electrically controlled stop mechanism located in a block, a track relay for said block, a home relay and a distant relay for said block, and circuit means controlled by the said relays for clearing the stop mechanism, when the block next in advance is occupied, a predetermined time after the track relay has been shunted byroccupancy of the said block, the circuit means includingan energizing circuit for the distant relay including a back point of the home relay and a back point of the track relay, and an energizing circuit for the home relay including a front point of the distantrelay.

4. An automatic train stop for railroads, comprising, in combination, an electrically controlled stop mechanism located in a block, a track relay for said block, a home relay and a distant relay for said block, and circuit means controlled by the said relays for clearingthe stop mechanism,

when the block in advance is occupied, a predetermined time after the track relay has been shunted by occupancy of the said block, the circuit means including an energizing circuit for the distant relay including a back point of the home relay and a back point of the track relay, and an energizing circuit for the home relay including a front point of the distant relay, and a. control Ycircuit for the stop mechanism requiring the distant relay down and the home relay up, to thereby insert a predetermined time interval between release of the track relay and operation of the stop mechanism.

THOMAS KITTREDGE. HERBERT D. BROOKS.

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