US2082971A - Apparatus for the control of highway crossing signals - Google Patents

Description

June 8, 1937. J. M. PELIKAN ET AL 2,082,971

APPARATUS FOR THE CONTROL OF HIGHWAY CROSSING SIGNALS Filed Sept. 4, 1936 2 Sheets-Sheet l Q INVENTORS fill/HM L'kan and .He .Ybung. n

NEW

THIER ATTORNEY June 8, 1937. J. M. PELIKAN ET AL APPARATUS FOR THE CONTROL OF HIGHWAY CROSSING SIGNALS Filed Sept. 4, 1956 2 Sheets-Sheet 2 s R n m. N m m v w m M R w m m QM R .lnlllls m 1+1 i 1 mm N5 E i ifi h W n fi mm m u mm D 3 Q mm R l? WK MW kw EN ,0 Q Q 5 H\ .|H|. H.| I I NU N\ \E w N K Patented June 8, 1937 uurrso stares E ATENT QFFIE APIEARA'EUS FOR, THE CONTROL OF HIGH- WAY CROSSING SIGNALS Pa, a corporation of Application September 9 Claims.

Our invention relates to apparatus for the control of highway crossing signals, and has for an object the provision of novel and improved apparatus controlled by a train approaching the O highway crossing for starting the operation of the signal in accordance with the speed of the train.

A feature of our invention is the provision of apparatus, of the type here involved wherewith the apparatus is restored and made efiective to time a second and following train that approaches the highway crossing prior to the leading train having passed completely over the crossing. A further feature of our invention is the provision of apparatus of the type here contemplated wherewith unnecessary operation of the apparatus by trains moving against the normal direction of trafllc is avoided. Other objects and advantages of our invention will appear as the 20 specification progresses.

Apparatus and circuits for the control of highway crossing signals similar to applicants apparatus and circuits are disclosed in the co-pending application for United States Letters Patent,

25 Serial No. 53,?59, filed December 19, 1935, by J. K.

lvlickley for Apparatus for the control of highway crossing signals, and of which copending application the instant application is an improvement.

30 We will describe two forms of apparatus em bodying our invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, 1 is a diagrammatic view of one form of apparatus em 35' bodying our invention, and Fig. 2 is a diagrammatic view of a second form of apparatus which also embodies the invention. Fig. 3 is a vertical sectional view showing one type of a rail microphone which may be used as the track instrument in the apparatus oi Figs. 1 and 2.

In each of the different views, like reference characters designate similar parts.

Referring to Fig. l, the reference characters la and to designate the track rails of a stretch of railway track over which trafiic normally moves in the direction indicated by an arrow, and which rails are intersected at grade by a highway H. A highway crossing signal S is located adjacentthe intersection and, here shown, is an audible signal in the form of an electric bell. It will be understood, of course, that our invention is not limited to this one form of signal and other forms such as a flashing light signal, a color light signal, gates, or barriers may he used if desired.

The track rails la and lb are divided by the Pennsylvania 4, 1936, Serial No. 99,424

usual insulated rail joints to form two track sections XY and Y-Z, which sections are traversed in the order named by a train approaching the highway crossing when moving in the normal direction of traffic. Each track section ispro vided with a track circuit comprising a battery 2 connected across the rails at one end of the section and a track relay TR plus a prefix corresponding to the location connected across the rails at the other end of the section. The section Y-Z is preferably arranged for its exit end Z to be adjacent the highway crossing and its entrance end Y to be far enough away from the crossing to provide a predetermined minimum warning period of operation of the signal S prior to the arrival of a train at the intersection when the train is operated at a speed not exceeding a certain prescribed speed, operation of the signal being initiated when the train reaches the location Y. Track section X---Y may be of any convenient length and in practicing our invention, the location X will usually be an automatic block signal location. In order to more easily understand the apparatus embodying our invention, we shall assume that the location Y is located in the rear oi the highway H a distance sufficient to provide seconds operation of the signal S prior to the arrival of a train at the intersection when the train is moving at 45 miles per hour, the op eration of the signal being as stated above initiated as the train enters the section Y-Z. Hence, under these conditions, the section Y-Z is substantially 1320 feet in length, since a train travelling at a speed of 45 miles per hour will advance approximately 1320 feet in 20 seconds.

The operation of the signal S is accomplished through the medium of an interlocking relay IR. The relay IR may be any one of several wellknown types of interlocking relays, and it is deemed SllffiClGl'lt for the present description to point out that the circuit controlling contact fingers and 3| are operated by the winding 5 of the relay, contact fingers 32 and 33 are operated by the winding 6, and these contact fingers are provided with an interlocking mechanism not shown whereby their movements are interlocked. The arrangement is such that contact finger 39 makes engagement with a full down contact 34 only when winding 5 is deenergized while winding 6 is energized, but with winding 5 energized or when deenergized subsequent to deenergizing of winding E, contact finger h! is held out of engagement with contact 34. Contact finger 3! is held in engagement with front contact 35 when winding 5 is energized and is released to break engagement therefrom when winding 5 is deenergized while winding 6 is energized. In the case winding 8 is deenergizcd while winding 5 is energized, the interlocking mechanism is operated and contact finger 3| is held in engagement with contact 35 even though winding 5 is subsequently deenergized.

Two track instruments MI and M2 are located spaced apart along the track section X-Y. These track instruments are preferably alike and may be any one of several types, and, as here shown, are rail microphones of a type described and claimed in the United States Letters Patent No. 1,83%,0T7, granted December 1, 1931, to A. J. Sorensen. Referring particularly to Fig. 3, the microphone MI is attached to the rail by means of a clamp 4 which is secured to the base of the rail by a lug 3 and a bolt IS. The microphone comprises an insulating housing l4 attached to the clamp 4 by a screw I6, and which housing contains two spaced vertically disposed metal electrodes E and El. The space between these electrodes is at least partly filled with carbon granules S3. The parts are so proportioned that under the conditions that the microphone Ml is not vibrated, the resistance between the electrodes E and El through the carbon granules is relatively low, but that when the microphone is vibrated and the carbon granules are agitated, the resistance between the two electrodes is increased several times its normal value. As stated above, the microphone M2 is preferably similar in construction to the microphone Ml.

Again looking at Fig. l, the microphone M2 is attached to the rail, as indicated by a dotted line, at a location V, and which location is a distance from the highway H sufficient to provide a predetermined period of operation of the signal S prior to the arrival of a train at the intersection when the train is operating at the maximum speed for all trains. operation of the signal being initiated when the train reaches location V. Thus, if 90 miles per hour be assumed as the maximum speed for all trains and the desired operating period for the signal S is seconds, the location V is substantially 2640 feet to the rear of the highway H and approximately 1320 feet to the rear of location Y. The microphone Ml is attached to the rail at a location U to the rear of location V. The distance between locations U and V is, in effect, a timing track section for determining the speed of a train and in accordance with which speed the time of starting the operation of the highway crossing signal is determined. This timing track section may be of any convenient length and is made to agree with the desired operating period of a time measuring means to be referred to hereinafter, and also in accordance with the speed of trains at this locality. In order to agree with the train speeds we have as sumed hereinbefore and to agree with a preferred form of time measuring means about to be described, we shall assume that the timing track section U-V is 270 feet in length. That is, the two rail microphones Ml and M2 are located 270 feet apart which is the distance traveled by a train in 4 seconds when operating at a speed slightly above 45 miles per hour. It is apparent that such timing track section does not require any subdivision of the track circuits as established for the usual wayside signal system, since these track instruments may readily be applied to the track rail at any point.

A repeater relay is associated with each of the rail microphones MI and M2, a relay Rl being associated with microphone MI and a relay R2 being associated with the microphone M2. Each of these relays is provided with a pick-up circuit and with a stick circuit. The pick-up circuit for relay RI comprises three branch paths over any one of which current may be supplied to the winding of the relay and the relay energized. The first branch path extends from the B terminal of any convenient source of current such a battery not shown, back contact 8 of track relay ZTR, line wire 9, winding of relay RI, and to the C terminal of the same source of current. The second. branch path includes battery terminal E, back contact Ill of relay R2, wire II to wire Q, and thence the same as traced for the first branch path. The third branch path includes battery terminal B, front contact I 2 of a relay DR to be referred to later, wire ll, wire 9, and as previously traced. The stick circuit for relay R5 includes battery terminal B, its own front contact iii, wire Hi, electrode E of microphone la-ii (see 3), the carbon granules I3 of the microphone, electrode El, wires 20 and 9, winding of relay if-t1, and to the opposite terminal C of the current source. The pick-up circuit for relay has two branch paths, one of which passes l 'izn battery terminal B over back contact 2| of track relay ZTR, line wire 22, winding of relay R12, and to the C battery terminal. The second branch path includes front contact 52 of relay DR, to he referred to later. The stick circuit for relay includes battery terminal B, its own front contact 23, wire 94, the electrodes and carbon granules of microphone wires and 22,

winding of the relay, and to the C battery ter- L minai. hence relays RI and R2 are retained energized normally by virtue of their respective stick circuit which in each case includes the associated rail microphone.

That unnecessary operation of the apparatus may be avoided when a train is moving against the normal direction of trafiic, a directional relay DR s provided and is controlled over a pick up circuit comprising battery terminal B, contact 3i-35 of relay IR, back contact 26 of relay ZTR, line wire 2], winding of relay DR, and to the C battery terminal. Relay DR may be retained energized over a stick circuit which includes back contact 28 of track relay XTR and its own front contact 36 as will. be readily understood by an inspection of Fig. l.

The apparatus includes a time measuring means operative to determine the time consumed by a train in traveling the timing section U-V and which means permits operation of the signal S when a train traveling this timing section at a speed above a predetermined speed, here assumed to be if: miles per hour, reaches the location V, and delays the starting of the operation of the signal S until the train reaches the location Y when the train speed is less than 45 miles per hour. As here shown, the time measuring means, indicated a whole by the reference character TM, consists of a slow pick-up slow release relay TE, and an associated stick relay 'I'ES which is slightly slow releasing in character. The arrangement such that a complete cycle of operation of relay TE is employed in timing a train over the timing section U-V. On the assumption the timing section U-V is 270 feet in length and the train speeds are as assumed hereinbefore, the pick-up period of relay TE is 2 seconds and its release period is 2 seconds, thereby providing a complete cycle of operation of 4 seconds. Relay TE is normally deenergized and is provided with an energizing circuit which passes from battery terminal B over back contact 31 of relay Ri, back contact 38 of relay TES, winding of relay TE, and to the C battery terminal. The associated stick relay TES is initially energized over a front contact 4% of relay TE, and may be retained energized by a stick circuit which includes battery terminal B, back contact 4| of relay TE, wire 39, two branch paths in parallel to wire 29, one of which paths includes back contact 42 of relay Rl, and the other of which includes back contact 53 of relay R2, thence over front contact 43 of relay TES, and winding of the relay to the C battery terminal.

The control circuit for energizing the winding of relay IR includes three branch paths. The first path is normally closed and includes battery terminal B, front contact 44 of relay R2, wire 45, front contact at of relay ZTR, winding 5, and to the C battery terminal. A second path is normally open and includes front contact :19 of relay TES, back contact 553 of relay TE, wire 5| to the wire 45, and thence as traced for the first path. The third path is also normally open and includes a front contact t? of the directional relay DR, Wires l8 and iii to wire 45 and as previously traced.

Normally, that is, when both track sections XY and Y-Z are unoccupied and their respec tive track relays XTR and ZTR are picked up, the repeater relays RI and R2 are retained energized by their respective stick circuits and the winding 5 is held energized over the circuit including front contact 44 of relay R2 and front contact 46 of relay ZTR.

In describing the operation of the apparatus in Fig. 1, we shall first assume a train traveling. at the maximum speed of 90 miles per hour approaches the highway crossing from the left. This train upon entering section X-Y shunts track relay XTR and that relay is released to close back contact 23. This operation performs no useful function at this time and need not be considered further for this train. When the head end of the train reaches location U, the microphone MI is vibrated and relay Rl is released due to the increase in the resistance of the microphone and to the resultant decrease in the energization of the relay. The release of relay RI and the closing of its back contact 3? cornpletes the energizing circuit for relay TE and that relay is energized to initiate its cycle of operation. The train traveling at 90 miles per hour advances from location U to location V in about 1 seconds and microphone M2 is vibrated and relay R2 is released. Release of relay R2 to close its back contact it supplies current to relay RI and that relay is picked up to open back contact 31 and thereby stop operation of relay TE. Since the pick-up period for relay TE is 2 seconds, further operation of the time measuring means is not effected after the arrival of the train at location V. Release of relay R2 to open front contact 44- upon the arrival of the train at location V causes winding 5 of relay IR to become deenergized since its other branch paths are now open, with the result that contact 3034 is closed and signal S is set into operation to warn highway users. It follows that signal S is set into operation upon the train reaching location V and 20 seconds operation of the signal prior to the arrival of the train at the intersection is effected since location V is substantially 26% feet from the highway. When the head end of the train enters section Y-Z and shunts track relay ZTR that relay is released to close its back contacts 8 and 2|. The closing of back contact 2| supplies current to relay R2 and that relay is picked up, and the closing of back contact 8 supplies current to relay Ri and that relay is retained energized after relay R2 is picked up even though the rear of the train might not yet have passed the location U, and microphone MI is still vibrated. Consequently, the relays RI and R2 are restored to their normal positions in response to the head end of the train entering the track section Y-Z. Operation of the signal S is continued while the train is in section Y-Z since the circuit of winding 5 is open at front contact 36 of relay ZTR. When the train proceeds over the crossing and vacates section YZ, the relay ZTR is picked up and winding 5 is reenergized to stop operation of the signal S.

We shall next assume a train approaches the highway crossing from the left traveling at a speed slightly less than 45 miles per hour. This train, upon entering section XY, shunts relay XTR the same as before. Furthermore, when the head end of the train reaches location U, relay R! is released and an operation of the relay TE is initiated the same as described for the first train. This train traveling at a speed slightly less than l5 miles per hour consumes something over 4 secends in passing from location U to location V. At the expiration of 2 seconds from the time the train reaches location U, relay TE picks up and closes its front contact if; which, in turn, picks up relay TES. With relay TES picked up, the energizing circuit for relay TE is open at back contact 38 and relay TE is deenergized and releases at the expiration of its 2 seconds slow release period. Relay TE upon releasing to close its back contact 3| completes the stick circuit for relay T1518 and that relay is retained energized as long as either relay Ri or R2 is down. Hence, when the head end of the train reaches location V and relay R2 is released to open front contact M interposed in the control circuit for winding 5, winding 5 is retained energized over the branch path which includes front contact 49 of relay TES and back contact 5!! of relay TE. Consequently, operation of the signal S is delayed until the train enters section YZ and shunts track relay ZTR to open the control circuit for winding 5 at the front contact 16 of that relay. Since location Y is substantially 1320 feet from the highway crossing substantially 20 seconds operation of signal S prior to the arrival of the train at the intersection is effected for this train operating at about 45 miles per hour. When the head end of this train enters section V-Z and shunted relay ZTR, the repeater relays El and R2 are restored to their normal positions the same as described for the first train. When relay R2 is picked up, the stick circuit for relay TES is opened and the time measuring means is restored to its normal position. It is clear that for all train speeds between 45 and 90 miles per hour the signal S is set into operation upon arrival of the train at the location V, but that for train speeds below i5 miles the time measuring means completes its cycle of operation and operation of the signal is delayed until the train enters the section Y-Z. Furthermore, in all cases, the relays Ri and R2 as well as the time measuring means are restored to their normal positions in response to the head end of the train entering the track section Y-Z.

Under the traffic conditions, where a second train enters section XY before the first train has completely passed out of that section or out of the section YZ, the relays RI and R2 are in a position to control the time measuring means and to time the second train through the timing section, if the first train advances and vacates section YZ prior to the head end of the second train reaching the location of microphone Ml. Hence, the apparatus will govern the operation of the highway crossing signal in accordance with the speed of the second train the same as for the first train.

In case a train operating against the normal direction of trafiic, that is, moving from the right to left in Fig. 1, enters section 1-2 and shunts track relay ZTR, the closing of back contact 26 of relay ZTR completes he picloup circuit [or the directional relay DR since the contact 55 lof relay IR is now held clos d by the interlocking feature of that relay, it being understood that winding 5 is controlled by trains approaching the highway from the right. Relay DR thus picked p, it will be retained energized over its stick circuit which includes back contact 28 of relay XTR until this train recedes from the crossing and vacates section. X Y. With directional relay DR picked up, the repeater relays R! and R2 are held energized while the train operates past the asso ciated rail microphone, relay RI being supplied with current over front contact ii! of relay DR, and relay Rt! being suppli d with current over front contact 52 of relay DR. Hence, unnecessary operation of the time measuring means by a train operating over track sections Y--Z and 1 against the normal direction cl traiiic is avoined. It is to be noted that relay DR when picked up completes at its front contact 4'! the third branch path for supplying current to the winding 5 of relay IR as soon as the train moving from right to left vacates section Y-Z. This releases the interlocking feature oi relay IR. Then if this train should reverse direction and again approach the highway the signal S will be operated as soon as the train reenters section Y--Z.

In Fig. 2, the track layout and apparatus is the same as in. 1 except a third track instrument M3 and an associated relay R3 are added. The track instrument M3 is preferably the same as the track instruments Ml and M2, and. as here shown, is a rail microphone which is operatively connected with a track rail at a location W along section Y-Z and which location is preferably near the entrance of the track section YZ. Relay R3 is controlled over a circuit extending from battery terminal B, back contact 54 of track relay XTR, line wire 55, back contact 56 of directional relay DR, electrodes and carbon granules of microphone M3, winding of relay R3, and to the C terminal of the current source. In this form of the invention, the pick-up circuits for relays RI and R2 as well as their stick circuits are normally closed. These pick-up circuits include back contacts 51 and 5a of relay respectively, as will be readily understood by an inspection of Fig. 2.

It is believed that the apparatus Fig. 2 may best be understood by describing the operation thereof, and to that end we shall. first assume train traveling less than miles per hour approaches the highway crossing from the left.

i This train, upon entering track section X-Y,

shunts track relay XTR which releases and back contact 54 with the result the relay is picked up leaving the two relays Psi and R2 held energized over their stick circuits. When the head end of the train reaches location U and causes release of relay RI due to vibration of microphone M current is supplied to the relay of the time measuring means and that relay i energized to start its cycle of operation. This energ' circuit may be traced from the B battery terminal over front contact 59 of relay back contact M of relay l-tl, wire El, back contact 62 of relay TES, winding of relay TE, and to the C battery terminal. At the end of 2 seconds, relay Till picks up and completes at its front contact fiii; pick-up circuit for relay TE; which circuit is the same as the energizing circult just traced for relay TE up to wire Bl, thence contact 63 of relay TE, winding of relay ii and to the battery terminal C. With relay once picked up, it completes a stick circuit at its front contact 64 and shunts around the front contact 63 of relay TE. Relay TES on ing up, also ope -s the energizing circuit for relay 'I'E back contact lid, and relay TE is deenergized and releases the end of 2 seconds its slow release period. When relay TE releases to close its bacl: contact (E35, current is supplied to the winding ol relay R2 over a circuit including ha contact of relay TE and front contact 5 relay TES. Since this train requires somehing over i seconds in advancing through the )ll UV, the above described cycle of relays TE and TES is completed to the arrival of the train at location V h the l cult that relay RE. is held energized subsequent to the microphone M2 being vibrated by the passing ith relay R2 thus rein. v tainerl encrgf ed, the control circuit for winding of re. and which circuit includes front contact relay R5! and front contact 67 of relay 2'36; 1 held closed until the train advances to location Y and enters section Y-Z to shunt tlz?"l l relay Z Hence, operation of the eilected for this train moving less per hour until the train occupies section When the train arrives at location W 1nd causes vibration of microphone M3, the relay is deenergized and releases to cornpiete the pick-up circuits for relays Hi and R2 and relay Rt is picked up, relay R2 having been retained energized by the time measuring means. Relay El, on piclting up, opens its back contact till and deenergizes the relay TES and that relay is restored to its normal deenergized position. Consequently, the relays Psi and R2 as well as the time measuring means are restored to their normal positions in response to the head end of the train reaching the location W which, as stated hereinbefore, is preferably close to the entrance of section YZ.

We shall next assume a train moving at a speed hi r than 45 miles per hour approaches the highway crossing from he left. This train shunts track relay XTR and causes relay R3 to be picked up the same as before. Furthermore, when the train reaches location U and vibrates microphone M! the relay R1 is released to close the energizing circuit for relay TE and start the operatin cycle of the time measuring means. This train, however, advances and reaches location V is than l seconds, and hence causes the release or relay 7352 before relays TE and TEE have had time to complete their full oper ating cycl Relay R2, upon releasing, opens the control circuit for winding 5 at front contact iii! and hence operation of the signal S is started when the train reaches location V. Again, relay R3 is released when the head end of the train reaches location W and the relays RI and R2 are restored to their normal energized positions,

operation of signal S being continued since relay ZTR is now shunted. It is to be seen, therefore, that relays RI and R2 and the time measuring means are in all cases reset and ready to time a second and following train which might enter the track section X-Y before the leading train has vacated that section or section YZ.

A train moving from the right to left in Fig. 2, and entering section YZ, shunts the track relay ZTR and that relay upon releasing closes at its back contact 68 the pick-up circuit for the directional relay DR which picks up and is then. retained energized over a stick circuit that includes back contact 54 of relay XTR and its own front contact 69 until such time as the train recedes from the crossing and vacates section X-Y. With directional relay DR picked up, the relay R3 is not energized when the relay XTR is released, and hence the relays RI and R2 are retained energized during the time this train receding from the crossing moves past the track instruments MI and M2, and unnecessary operation of the time measuring means is avoided. When this train moving from the right to the left vacates section Y--Z relay ZTR picks up to energize winding 5 of relay IR and release the interlocking feature of that relay. If this train should now reverse its direction and approach the highway the winding 5 is deenergized and the signal is operated when the train enters section Y-Z and shunt relay ZTR.

Although we have herein shown and described only two forms of apparatus embodying our invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of our invention.

Having thus described our invention, what we claim is:

1. In combination, a stretch of railway track intersected by a highway and formed into a track section to one side of the intersection, a track circuit for said section including a track relay, a highway crossing signal located at the intersection, two track instruments capable of operation by a train and located one at each of two selected locations which a train passes prior to entering said track section in approaching the intersection, a normally energized first relay governed by the track instrument nearer the section and, effective to start operation of the signal when deenergized in response to the head end of a train reaching the location of that instrument, a normally deenergized time measuring means effective when energized a predetermined time interval to render said first relay inefiective to start operation of the signal, a normally energized second relay governed by the track instrument more remote from the section and effective to energize the time measuring means when deenergized in response to the head end of a train reaching the location of that instrument, other means including a front contact of the track relay to operate the signal, and means controlled by a train to restore said first and second relays as well as the time measuring means to their normal positions in response to the head end of a train entering said track section.

2. In combination, a stretch of railway track intersected by a highway and formed into a track section to one side of the intersection, a track circuit for said section including a track relay, a highway crossing signal located at the intersection, two track instruments capable of operation by a train and located one at each of two selected locations which a train passes prior to entering said track section in approaching the intersection, a normally energized first relay governed by the track instrument nearer the section and effective to start operation of the signal when deenergized in response to the head end of a train reaching the location of that instrument, a normally deenergized time measuring means effective when energized a predetermined time interval to render said first relay ineffective to start operation of the signal, a normally energized second relay governed by the track instrument more remote from the section and effective to energize the time measuring means when deenergized in response to the head end of a train reaching the location of that instrument, other means including a front contact of the track relay to operate the signal, and means including a back contact of said track relay effective to restore said first and second relays as Well as the time measuring means to their normal positions.

3. In combination, a stretch of railway track intersected by a highway and formed into a track section to one side of the intersection, a track circuit for said section including a track relay, a highway crossing signal located at the intersection, two track instruments attached to a track rail one at each of two selected locations which a train passes prior to entering said track section in approaching the intersection, a normally energized first relay governed by the track instrument nearer the section and effective to start operation of the signal when deenergized in response to the head end of a train reaching the location of that instrument, a normally deenergized time measuring means effective when energized a predetermined time interval to render said first relay ineffective to start operation of the signal, a normally energized second relay governed by the track instrument more remote from the section and effective to energize the time measuring means when deenergized in response to the head end of a train reaching the location of that instrument, other means including a front contact of the track relay to operate the signal, means including a back contact of said first relay and a back contact of the track relay in parallel to energize said second relay, and other means including a back contact of the track relay to energize said first relay.

4. In combination, a stretch of railway track intersected by a highway and formed into a track section to one side of the intersection, a track circuit for said section including a track relay, a highway crossing signal located at the intersection, two track instruments attached to a track rail one at each of two selected locations which a train passes prior to entering said track section in approaching the intersection, a normally energized first relay governed by the track instrument nearer the section and effective to start operation of the signal when deenergized in response to the head end. of a train reaching the location of that instrument, a normally deenergized time measuring means effective when energized a predetermined time interval to render said first relay inefiective to start operation of the signal, a normally energized second relay governed by the track instrument more remote from the section and effective to energize the time measuring means when deenergized in response to the head end of a train reaching the location of that instrument, other means including a front contact of the track relay to operate the signal, a third track instrument attached to a track rail along said track section, a third relay governed by said third track instrument and effective to restore said first and second relays as Well as the time measuring means when operated in response to the head end of a train reaching the location of the third instrument.

5. In combination, a stretch of railway track intersected by a highway and formed into a track section to one side of the intersection, a track circuit for said section including a track relay, a highway crossing signal located at the intersection, two track instruments attached to a track rail one at each of two selected locations which a train passes prior to entering said track section in approaching the intersection, a normally energized first relay governed by the track instrument nearer the entrance of said section and effective to start operation of the signal when deenergized in response to the head end of a train reaching the location of that instrument, a normally deenergized time measuring means effective when energized a predetermined time interval to render said first relay ineffective to operate the signal, a normally energized second relay governed by the track instrument more remote from the entrance of the section and effective to energize the time measuring means when deenergized in response to the head end of a train reaching the location of that instrument, other means including a front contact of the track relay to operate the signal, a third track instrument attached to a track rail substantially at the entrance of the track section, a third re lay, an energizing circuit for the third relay including a contact actuated oi the third instrument and which contact is opened when a train passes the location of the third instrument, means including a back contact of said third relay to energize said first relay, and other means including another back contact of said third relay to energize said second relay.

6. In combination, a stretch of railway track intersected by a highway and formed into a track section on one side of the intersection, a highway crossing signal located at the intersection, a track circuit for the section including a track relay, 9, track instrument attached to a rail at a location which a train passes prior to entering the section in approaching the intersection, a time measuring means effective at times to govcm the operation of said signal, a first relay governed by the track instrument to control said time measuring means in response to a train passing the location of the instrument, a signal controlling interlocking relay including a Winding energized over a front contact of track relay, a directional relay, a pick-up circuit for the directional relay including a front contact operated by said winding and a back contact of the track relay, a stick circuit for the directional relay including a back contact of another track relay which a train shunts subsequent to pass-- ing through said track section in receding from the intersection, and means including a front contact of the directional relay to render said first relay ineffective to operate the time measur ing means when the receding train passes the location of said instrument.

7. In combination, a stretch of railway track intersected by a highway and formed into a track section on one side of the intersection, a highway crossing signal located at the intersection, a track circuit for the section including a track relay, a track. instrument attached to a rail at a location which a train prior to entering the section in anproaching the intersection, a control relay gov rned by the rack instrument and effective to cause the signal to be operated in response to a train passing the location of said instrument, a directional relay, a pick-up circuit for said directional relay including a back 10 contact of said track relay and another contact controlled by a train and closed when a train enters the section the end adjacent the intersection, sticlr circuit for said directional relay and includin a back contact of another track 15 relay which a train shunts subsequent to passing through said track section in receding from the intersection, and means including a front contact of the directional relay to render the control relay ineffective to operate the signal when the 2 0 receding train the lO'JEttlOll of said instrument.

8. In combination, a. stretch of railway track intersected by a highway, a highway crossing signal located the intersection, two track in-- struments capable of operation by a train and located one at each of two selected locations to one side of the intersection, a normally energized relay governed by the track instrument w arcr the intersection and effective to start 0p-- I10 oration oi signal when deenergized in response to the head end of a. train reaching the location of that instrument, a normally deener-- gized time measuring moans effective when energized predew' rmined time to render said first relay ineffective to operate the signal, a normally energi ed second relay governed by the track instruinent more remote from the intersection and effective to men, ne measuring means when deener zed in resnoi -'e to the head end of 40 a train reaching tle location of that instrument, and r. controlled by a train upon reaching a fixed point between the track strunient nearthe intersection and the intersection to enersaid first and second rela s irre ectiye of the associated track instruments.

9. In combination, a stretch of rai r/ay tracl; intersected by a highway, a highway crossing signal located the intersection, two track instruments capable of operation by a train and located one at each of two selected locations to one side of the inte ction, a first relay, a normally cloei stick circuit for said first relay and including the trash instrument nearer the intersection, operating ineans controlled .ey said relay and effective to operate said s gnal he. said relay is deenergized, tune moasur' erative w' terval to r ider said opera cctivc to operate the sig al, a sec-3 y, a normally closed sticl; circuit for said second relay and incluclng the track instrument more remote from the intersection, means controlled by sa d second relay when ergized to act? c meas- JOHN M. PE. IKAN. HENRY S. YOUNG.

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