US2113642A - Apparatus for the control of highway crossing signals - Google Patents

Description

April 12, 1938. A. E. DODD ET AL APPARATUS FOR THE CONTROL OF HIGHWAY CROSSING SIGNALS Filed July 28, 1956 2 Sheets-Sheet l 4 INVENTOR 5 Arthur .Dodd and I H S. Y any BY RN NW Q mg w o N N 4 ML F Q v N HHHKR H hm SW SN Al N No K A Q N THEIR ATTORNEY A. E. DODD ET AL April 12, 1938.

APPARATUS FOR THE CONTROL OF HIGHWAY CROSSING SIGNALS Filed July 28, 1936 2 Sheets-Sheet 2 .Dodd and S. Young.

INVENTOR AmN T/YE'IR ATTORNEY Arthur He BY $3 Q8 $5 mkg w WW M ma w an N NW mm jig .m\\ m m UH i 5 no Patented Apr. 12, 1938 UNITED STATES FATE APPARATUS Arthur E. Dodd and burg, Pa., assignor Signal Company, S

"r OFFICE WAY f Pennsylvania FOR THE CONTROL OF HIGH- CROSSING SIGNALS Henry S. Young, Wilkinss to The Union Switch & wissvale, Pa., a corporation Application July 28, 1936, Serial N0. 93,028

Our invention relates to 15 Claims.

apparatus for the control of highway crossing signals, and particularly to apparatus controlled by a train ap proaching a highway crossing crossing signal in acof the train.

operation of a highway cordance with the speed for governing the A feature of our invention is the provision of novel and improved apparatus controlled by a train as it travels two or more consecutive track Sections in approaching a highway crossing for initiating the operation signal if the train exceeds of a highway crossing a particular speed predetermined for each track section. Another feature of our invention is the provision of apparatus of the type here involved for preventing an accidental interruption of a circuit associated vision of apparatus of the which is governed by track 1 features and advantages of appear as the We will describe two form type contemplated nstruments. Other our invention will specification progresses.

s of apparatus embodying our invention, and will then point out the novel features thereof in claims.

Apparatus controlled by a train as it travels two or more consecutive track sections in approaching a fixed location measuring means trol if the train exceeds the to operate a time for establishing a signal conlimit of speed predetermined for any track section, has been proposed in the United States application for Letters Patent Serial No. 61,561, filed January 30,

1936, by George W. Baughman, for Railway signaling apparatus. Our invention may be considered an improvement on plication.

In the diagrammatic view of one the Baughman apaccompanying drawings, Fig. 1 is a form of apparatus embodying our invention, and wherewith the :apparatus is governed by a train through the :medium of track circuits of insulated track sections.

Fig. 2 is a diagrammatic view of a second form of apparatus embodying our invention, and wherewith the apparatus is governed by a train through the medium of track instruments :placed at selected points, the

railway track being thus formed into track sections the limits of which are defined by the locations of the track instruments.

In each of the different views,

like reference parts. eference characters 1 uring and signal operating section,

Ia and lb designate the track rails of a stretch of railway over which traflic normally moves in the direction indicated by an arrow, and which track rails are intersected by a highway H. The track rails la and II) are formed by the usual insulated rail joints into four track sections IT, 2T, ST, and lT which a train travels successively in the order named in approaching the highway H when it is traveling in the normal direction of trafiic. These track sections are each provided with a track circuit consisting of a source of current such as a battery 2 connected across the rails at one end of the section and a track relay indicated by the reference character R plus a prefix corresponding to the section connected across the rails at the other end of the section. It is to be observed that the track relays ITR, 2TB, 3TB and ATR- associated with the insulated track sections IT, 2T, 3T and 4T, respectively, are traffic controlled relays which are normally energized and which become deenergized in response to a train entering the associated track section. A repeater relay 2TPR is controlled over a front contact 20 of the track relay ZTR. As will appear hereinafter, the respective lengths of these several track sections hold a definite relationship with respect to each other, and which relationship is dependent upon the desired warning period of the highway crossing signal prior to the arrival of a train at the intersection, and also upon the minimum and maximum speeds of the trains passing over the intersection. The track section IT is a time measuring section, section 2T is a combined time measand sections 3T and AT are operating sections. The length of each section IT and 2T is directly proportional to a speed limit predetermined for the section, and they bear a selected relation as to the distance between the highway crossing and the near end of the section. This distance is such that in each case substantially the same interval of time is required for a train to move from the near end of the section to the highway crossing at the respective predetermined speed limits. The function of such selected lengths for the several track sections will be described more fully hereinafter.

Two highway crossing signals SI and S2 are located adjacent the intersection and are here shown as flashing light highway crossing signals. In accordance with standard practice, these two signals are set for one to be exhibited to highway trafiic approaching the crossing in one direction and the other signal to be exhibited to highto be explained later.

way traffic approaching the crossing in the opposite direction. The signal S2 is also provided with an audible indication in the form of an electric bell EB. It will be understood, of course, that our invention is not limited to this specific form of highway crossing signal, and other forms such as wigwags, gates, or barriers may be used if desired.

The immediate control of signals SI and S2 is effected by a flasher relay FR. and an interlocking relay KB. The flasher relay FR may be any one of several types which are well-known to the art. It is deemed sumcient for this application to point out that when relay PR is deenergized, its two contact fingers 6 and I arebiased to a mid position, that is, to the position illustrated in the drawings, but that when the relay is energized,

these contact fingers are oscillated between two extreme positions which are indicated on the drawings by dotted lines, the rate of oscillation being, say, for example, 30 cycles per minute. Contact finger 6 in its mid position makes engagement with two mating contacts 8 and 9, but when swung to its left-hand position, it breaks engagementwith contact 8, and when swung to its right-hand position, it breaks engagement with contact 9. Likewise, contact finger l in its mid position makes engagement with two mating contacts I9 and II, and breaks engagement with the contacts is and H in the left-hand and righthand positions, respectively.

Relay XR is preferably a standard type interlocking relay. The winding 3 of relay XR is controlled by the apparatus associated with the track sections to the left of the highway H in a manner The winding !9 of relay XR may be governed in the usual marmer by apparatus responsive to traffic approaching the highway H from the right but which apparatus is not shown in the drawings since it forms no part of our invention. When winding 3 of relay XR is deenergized and its back contacts 4 and I3 are closed, current is supplied to the operating winding of relay ER and to the signals SI and S2. The closing of back contact 4 of relay XR completes a circuit extending from the B terminal of any convenient source of current such as a battery not shown over back contact 4, wire 5, winding of relay FR, and to the C terminal of the current source, and relay FR is set into operation. A branch circuit extends from wire 5 over wire I2, operating winding of bell EB and to the C battery terminal, and the bell sounds an alarm. The closing of back contact I3 of relay XR completes operating circuits extending from the BX terminal of a source of current such as a line transformer, not shown, over back contact I3, wire M, contact fingers 6 and "I of relay FR, thence to the lamps I5 and I6 of signal SI, and to the lamps I1 and I8 of signal S2, and to the CX terminal of the current source, as will be readily understood by an inspection of Fig. 1. It follows that signals SI and S2 are normally dark and the bell EB is silent, but that release of winding 3 of relay XR and the closing of contacts 4 and I3, causes the bell EB to sound an alarm, and the relay FR to be operated and the lamps of each of the signals SI and S2 to be alternately flashed. It is to be noted that should relay FR fail to operate, the lamps of the signals SI and S2 are continuously illuminated.

The control apparatus located at the intersection also includes a time measuring means which may take different forms, and which, as here shown, consists of three associated relays SR,

'trical relays.

TR, and I'PSR. Relay SR is a direct current neutral relay which functions as a control relay for the other two relays TR and TPSR. Relay TR is a slow acting relay having slow to pick up characteristics, and relay TPSR is slow releasing 5 in character. The slow acting relay TR may be of the type described in the United States Letters Patent No. 1,966,965, granted July 1'7, 1934,

to Branko Lazich and H. E. Ashworth for Elec- Relay TR is so proportioned and 10 adjusted that its contact arm 21 is moved and makes engagement with a front contact 26 only after the winding of the relay has been energized a predetermined period say, for example, secends; but that upon deenergization of the wind- 15 ing of the relay, contact arm 21 immediately drops from whatever position it has advanced back to its normal position. A contact finger 28 is operatively connected with the contact arm 21 as indicated by a dotted line in the drawing, to check the normal position of arm 27, the arrangement being'such that contact finger 28 engages a stationary contact 29 only when the contact arm 27 occupies its full normal position. As will shortly appear, the relays of the time measuring means are successively operated as a train travels the sections IT and 2T.

Normally, that is to say, when the track sections are all unoccupied, the track relays are each energized by virtue of the track circuit in which .30 each is included, and the winding 3 of relay XR is energized over a circuit which may be traced from the B battery terminal over front contact 33 of track relay 2TR, front contact 3| of repeater relay ZTPR, front contact 32 of track relay 3TR, 135 front contact 33 of relay 4TR, winding 3, and to the C terminal of the current source. The relays SRRI'R, and TPSR of the time measuring means, as well as a relay 3SR to be referred to later, are normally deenergized. 40

In describing the operation of the apparatus of Fig. 1, we shall assume a-permissible variation in the warning period of signals SI and S2 prior to arrival of a train at the highway of 20 to 33 seconds, and that the train speeds are between a minimum speed of 25 miles per hour and amaximum speed of 80 miles per hour. To agree with this permissible variation in the warning period, the operating time of the'slow acting relay TR is preferably l5 seconds. On the above assumptions, the track sections IT, 2T, 3T, and 4T are preferably 1170, 686, 520, and 1144 feet in length, respectively.

We shall first consider the operations that take place in response to a train moving through the .55 track sections at the assumed minimum speed of 25 miles per hour, or 36.6 feet per second. The train, upon entering section 5 T, shunts track relay ITR, and that relay, upon releasing, completes at its back contact 34 an energizing circuit for the control relay SR of the time measuring means, and relay SR is picked up. This circuit includes battery terminal B, back contact 34 'of relay ITR, wire 35, back contact 36 of relay 3SR, front contact 31 of relay ZTPR, front con- 5 tacts 38, 39, and 49 of relays ZTR, 3TR, and 4TR, respectively, check contact 2829 of relay TR, winding of relay SR, and the C terminal of the same source of current. The control relay SR on picking up completes at its front contact 4| 2. shunt path around the check contact 2B-29, and completes at its front contact 42 a simple operating circuit for the slow acting relay TR. Relay TR requires 15 seconds operating time to close its contact 26'2'I, and hence when the train has advanced approximately 550 feet in section IT, which is 1170 feet in length, the relay TR picks up and completes a pick-up circuit for relay TPSR, this pick-up circuit including a front contact 43 of relay SR as well as the contact 2621 of the slow acting relay TR. Relay TPSR at once picks up and closes its front contacts 44 and 45. The closing of front contact 44 prepares a stick circuit network by which relay TPSR is subsequently retained energized. This stick circuit network may be traced from B battery terminal over front contact 46 of repeater relay ZTPR, back contact 41 of track relay ZTR, front contact 48 of relay 3TR, front contact 49 of relay 4TB, front contact 44 and winding of relay TPSR, and to the C battery terminal. A branch path for this circuit network extends from the B battery terminal over front contact 50 of relay 3SR, back contact 5! of relay STR, and thence as previously traced. It is to be noted that with relays SR and TPSR picked up and their respective front contacts 52 and 45 closed, the winding 3 of relay XR is provided with two branch paths in multiple over either one of which it may receive current, front contact 33 of relay 4TB being also included in these branch paths.

When this train advances and enters section 2T, the track relay 2TR is shunted and is released. The repeater relay ZTPR is now deenersized and releases at the end of its slow release period. The circuit for control relay SR is now open at front contact 38 of relay 2TR and relay SR is released and in turn deenergizes relay TR which immediately drops its contact arm 21 to the normal position and recloses check contact 28 29. Release of relay SR also opens the pick-up circuit of relay TPSR but that relay is retained energized during the slow release period of relay ZTPR over the stick circuit which includes front contact 46 of relay 2TPR and back contact 41 of relay 2TR. At the expiration of the release period of relay ZTPR, relay ZTPR releases and opens this stick circuit for relay TPSR and the latter relay is deenergized and releases at the end of its slow release period. During the period relay TPSR is up and relay ZTPR is down, a second energizing circuit for control relay SR is formed and relay SR picks up to start a new operation of relay TR. This second circuit for relay SR includes B battery terminal, front contact 45 of relay TPSR, front contact 32 of relay 3TR, back contact 53 of relay ZTPR, back contact 54 of relay 2TR, front contacts 39 and 40 of relays 3TR and 4TR, respectively, check contact 2829, winding of relay SR and the C terminal. Relay SR is retained energized over its own front contact 52 and the above traced second circuit subsequent to the release of relay TPSR. It is to be noted that the two slow release relays 2TPR and TPSR are released in sequence and the total slow release time of the two relays is available for effecting the operation of releasing relays SR and TR and reenergizing relay SR. We have found that relays 2TPR and TPSR when of the usual construction for slow release relays provide an interval suficient to bridge the time required for relay TR to be reset and close its check contact, and the relay SR to be picked up, when the two slow release relays are released in sequence.

The normal energizing circuit of winding 3 of relay XR is opened at front contact 30 when relay 2TR is released in response to the train entering section 2T, but winding 3 is supplied with current over the branch path including front contact 45 of relay TPSR subsequent to the release of relay 2TR, and then over the branch path including front contact 52 of relay SR subsequent to the release of relay TPSR. Furthermore, relays 2TR and 2TPR when released, close a pickup circuit for the relay 3SR, and that relay is energized and picks up at the end of a slow pickup period. This circuit includes B battery terminal, back contact 2| of relay ZTR, back contact 22 of relay ZTPR, front contact 23 of relay 3TR, winding of relay 3SR, and the C battery terminal. Operation of relay 3SR at this time, however, performs no useful function except to prepare the stick circuit for relay TPSR at front contact 55; It follows that entry of the train into the track section 2T is effective to cause the time measuring means to be reset to its normal position and a new operation thereof initiated, to transfer the control of winding 3 of relay XR from its normal or main energizing circuit, which is governed by the track circuits to its two branch paths which are controlled by relays SR and TPSR of the time measuring means, and to energize relay 3SR.

By the time the train traveling 25 miles per hour advances approximately 550 feet in section 21, which is 686 feet in length, the relay TR is again operated to close its contact 2627 and the relay TPSR is again picked up. When the train passes into section 3T, the track relay 3TR is shunted and is released. The opening of front contact 39 of track relay 3TR removes current from the control relay SR and that relay is released, and, in turn, the slow acting relay TR is deenergized and is restored to its normal position. The relay TPSR is retained energized this time over its stick circuit which includes the front contact 50 of relay 3SR and back contact 5! of track relay 3TR, relay 3SR being held up over a stick circuit including back contact 24 of relay 3TB. and its own front contact 25. Winding 3 of relay XR is energized subsequent to the release of relay SR over the branch path which includes front contact 45 of relay TPSR. Relays SR and TR are not again reenergized since the energizing circuit for relay SR remains open at front contact 39 of relay 3TR. Consequently, relay TPSR is held energized over its stick circuit during the time the train is advancing through the track section 3T.

When the train enters section 4T, track relay 4TR is shunted and releases to open its front contact 33 which is interposed in the branch paths as well as in the main circuit for the winding 3. With winding 3 deenergized and its back contacts 4 and I3 closed, operation of signals SI and S2 is effected in the. manner set forth hereinbefore. Relay TPSR is now deenergized and restored to its normal position since its stick circuit is open at the front contact 49 of the track relay 4TR. It follows that the warning period prior to the arrival of the train at the intersection is substantially 31 seconds since the track section 4T is 1144 feet in length and the train is operating at about 36.6 feet per second.

We shall assume next that a train approaches the highway H travelling at the maximum speed of miles per hour or 117.3 feet per second. When the train enters section IT and shunts track relay I TR, that relay is released and closes at its back contact 34 the energizing circuit for control relay SR the same as described for the first train. With relay SR picked up the slow acting relay TR is energized to initiate its operation. Contact 25-21 of relay TR is not closed, however, prior to the train entering the track section 2T since this train consumes only about 10 seconds in advancing through the section IT, whereas the operating time for relay TR is 15 seconds. Consequently, relay TPSR. is not picked up prior to the shunting of the track relay 2TB, with the result that when front contact 38 of track relay 2TB. is opened and relay SR. is deenergized, this relay remains deenergized inasmuch as its second energizing circuit which includes back contact E l of relay 2TB is open at front contact 45 of the relay'TPSR. Release of the track relay ZTR and the opening of its front contact 39 deenergizes the winding 3 of relay XR since the branch paths are now both open. Hence, operation of signals SI and S2 is initiated when the train operating at the maximum speed of 80 miles per hour enters the track section 2T. The warning period of signals SI and S2 prior to the arrival of the train at the intersection 'is substantially 20 seconds since the total distance from the exit end of section IT to the highway is 2350 feet.

It is apparent that for all trains exceeding the speed of 53. miles per hour or about 78.4 feet per second, in section IT, operation of the highway crossing signals is initiated in response to the train entering section 2T since all such trains reach the exit of section IT in less than 15 seconds, the operating time of the slow acting relay TR. A train moving 53.4 miles per hour consumes substantially 30 seconds in advancing from the exit end of track section IT to the highway. Thus for train speeds between 80 and 53.4 miles per hour the variation in the warning period of the highway crossing signal is within the assumed permissible variation.

If a train is operating at a speed slightly less than 53.4 miles per hour and consumes 15 seconds in traveling track section IT and entering section 2T, the slow acting relay TR is operated and relay TPSR is picked up prior to the time the track relay 2TB is shunted. With relay TPSR picked up, it is retained energized by virtue of its stick circuit which includes the back contact 47 of relay 2TB and the front contact 45 of the repeater relay ZTPR, and a second operation of the time measuring means is effected in the manner described for the train. operating at 25 miles per hour. Likewise, winding 3 of relay XR is retained energized over its branch paths including front contact 52 of relay SR and front contact 35 of relay TPSR for such train speed.

If a train exceeds a speed of 31.2 miles per hour or 45.8 feet per second and consumes less than 15 seconds in operating over track section 2T, the highway crossing signals are set into operation in response to the train entering the section 3T, since the slow acting relay TB is not operated the second time to close its contact 2521 and cause the energization of relay TPSR prior to the shunting of the track relay Under such circumstances, the release of track relay 3TH to open its front contact 39 causes relays SR and TR to be restored to their normal positions with the relay TPSR deenergized, with the result the winding 3 is without current and releases to startthe operation of the highway crossing signals. The total distance from the exit end of section 2T to the highway is 166 feet, and hence the warning period of the highway crossing signals for a train operating a little above 31.2 miles per hour is approximately 33 seconds. i

If the train is moving a little less than 31.2 miles per hour in section 2T and consumes some thing over 15 seconds in advancing therethrough,

and relay TR. has completed its second operation and picked up relay TPSR prior to the shunting of track relay 3TB, the relay TPSR is retained energized over its stick circuit including back contact 5| of relay 3TB. Under these circumstances, winding 3 of relay XR is retained energized over its branch path including front contact 45 of relay TPSR.

It is to be seen, therefore, that for train speeds above 53.4 miles per hour, the predetermined speed for section IT, the signals SI and S2 are set-into operation in response to the train entering track section 2T. The warning period prior to the arrival of the train at the crossing is in this case within the permissible variation of 20 to 33 seconds, since the distance between the highway and the near end of section IT is such that a train operating at 53.4 miles per hour consumes substantially 30 seconds. and a train operating at the maximum speed of 80' miles per hour consumes about 20 seconds in advancing therethrough. For train speeds between 53.4 and 31.2 miles, the predetermined speed for section 2T, the highway crossing signals are set into operation in response to the. train entering section 3T. Again, the warning period is within the permissible variation, since the distance between the highway and the near end of section 2T is such that a train operating at 31.2 miles per hour consumes approximately 33 seconds and a train operating at a speed of a little less than 53.4 miles per hour consumes approximately ,20 seconds in advancing therethrough. For train speeds between 31.2 miles per hour and the assumed minimum speed of 25 miles per hour, the

operation of the highway crossing signals is delayed until the train enters the section 4T and a warning period of at least 20 seconds is effected, since the distance from the highway to the near end of section 3T is such that a train operating at the speed of,3l.2 miles per hour consumes about 22 seconds in advancing therethrough.

It should be pointed out that for certain train speeds the pickup circuit for relay TPSR is opened almost immediately after having been closed. The stick circuit for relay TPSR. assures that if this relay is once picked up by virtue of the slow acting relay TR having completed its operation, it remains energized although relay TR is reset almost immediately, such operation of relay TR occurring with certain train speeds. Consequently, full release period of relay TPSR along with the release period of relay ZTPR for resetting the slow acting relay TR and reenergizing the control relay SR to initiate a new operation of relay TR. under all conditions of train speeds are assured.

The slow pickup relay SSR, is provided so that an interruption of the track circuit for the section 3T will not complete the stick circuit for relay TPSR of the time measuring means while the train is approaching in section IT and the time measuring means is being reset as the train enters section 2T. Relay 3SR. is so proportioned that its slow pickup period is slightly greater than the time required for relay TPSR to release. Assume a medium speed train, say 60 miles per hour, is traveling through. track section IT and relay TR has operated'and picked up relay TPSR, and

7 then the track circuit for section 3T is accidentally interrupted and track relay 3TB is released at the time the relays SR and TR are being reset. The relays SR and TR would be restored to their normal positions because the front contact 39 interposed in the energizing circuit of relay SR is now open. The relay TPSR also would be released because its stick circuits are open at the front contact '50 of relay 3SR, and front contact 46 of relay ZTPR. Hence, operation of the highway crossing signals is initiated at once and their operation is continued until the train has advanced over the crossing. Were the relay 38R not provided and the track circuit for section 3T accidentally interrupted under the conditions set forth above, the relay TPSR might be retained energized over its stick circuit including back contact 5| of relay 3TR and operation of the highway crossing signals might not be initiated for suchmedium speed trains until the train entered the final operating section 4T. However, with the apparatus constructed in the manner disclosed in Fig. 1 shortening of the warning period of the highway crossing signal in the case of a track circuit interruption at some distance in advance of a train is avoided.

It will be understood, of course, that our invention is not limited to the specific train speeds, variation in Warning periods, and lengths of track sections assumed in describing the operation of the apparatus of Fig. 1, and a study of the invention will disclose the flexibility of the system.

In Fig. 2, the track rails la and lb of a stretch of railway are arranged in a single insulated track section 5T, which is intersected by a highway H adjacent the exit end of the section. The track section ET is provided with the usual track circuit including a track relay 5TR. Three track instruments RE, R2, and R3 are associated with the track rail lb of the track section 5T, these track instruments being located at locations BT, CT and DT, respectively. These track instruments may be any one of several diiferent types and are shown conventionally for the sake of simplicity since their specific structure forms no part of our invention. One form of track instrument that may be used is disclosed and claimed in a copending application for Letters Patent Serial No. 54,500, filed December 14, 1935, by H. G. Witmer, for Circuit controlling instruments. In this form of track instrument a circuit controlling contact is biased to a closed position and. is operated to an open position by the vibration set up in the track rail by a train wheel passing over the point at which the instrument is attached to the rail. It will be understood, of course, that our invention is not limited to this one form of track instrument and other forms may be used.

The significant point is that each track instruthe train has passed. Contacts 61-68 and 58-59 of track instruments R2 andR3, respectively, are operated in a similar manner.

' The distances ATBT, BT-CT, CT-DT, and DT-ET bear a relationship to each other similar to that described for the track sections IT, 2T, 3T, and lT of Fig. 1. That is to say, the stretch of railway of Fig. 2 is formed into four track sections the lengths of which are defined by the insulated section 5T and the locations of the track instruments. Hence, the section AT-BT constitutes a time measuring section, section BT-CT a combined time measuring and operating section, and sections CT-DT and DT-ET operating sections in the same manner as the track sections of Fig. 1.

Each track instrument controls a relay designated by the reference character R plus a prefix to indicate the location of the track instrument. The control circuits for each of these relays are the same and. it is thought that a description of the circuits for one will suffice for an understanding of all. Relay DR associated with track instrument R3 is provided with a pickup circuit which includes battery terminal 13, front contact 51 of track relay 5'I'R, winding of relay DR, and the 0 battery terminal; and is also provided with a stick circuit which includes its own front contact 60 and the contact 58-59 of track instrument R3. Relay BR controlled by the track instrument RI governs over its front contact 6| a slow release repeater relay BPR. It is to be observed that the relays BR, CR and DR associated with the track sections BT-CT, CTDT and DTET, respectively, as well as the relay 5TR of track section 5T, are traffic controlled relays which are normally energized and which become deenergized in response to a train entering the associated track section.

The highway crossing signals SI and S2 of Fig. 2 are governed by a flasher relay FR and an interlocking relay XR in the same manner as described in Fig. 1. Furthermore, the control apparatus includes a time measuring means which consists of three relays SR, TR, and TPSR the same as in Fig. 1.

In Fig. 2, certain of the contact fingers of the several relays are shown remote from the winding of the relay in order to simplify the drawings as much as possible. In each case the contact finger is given a reference character corresponding to the associated relay plus a distinctive numeral, and each such contact finger is illustrated in the position corresponding to the position of the relay.

To prevent an accidental interruption of the circuit for relay CR while a train is advancing through the first timing track section from shortening the warning period, a slow pickup relay BSR is Provided. This relay BSR is controlled over a pickup circuit which includes back contacts 62 and 63 of relays BR and BPR, respectively, as well as a front contact CRM; and is then retained energized by a stick circuit which includes a back contact 65 of relay CR and its own front contact 66.

In describing the operation. of the apparatus.

of Fig. 2, we shall assume that the maximum and minimum train speeds, and the permissible variation in the warning period are the same as assumed in Fig. 1. Hence, the preferred operating time for relay TR of the time measuring means is seconds, and the track sections AT-BT, BT-CT, CT-DT, and DTET are 1170, 686, 520, and 1144 feet in length, respectively.

Taking the case of a train. operating at the minimum speed of miles per hour, the track relay 5TR is shunted and releases in response to the head end of the train. passing the location AT. Release of relay 5TR opens the pickup circuit for each of the relays BR, CR, and DR, and these relays are retained energized over their stick circuits governed by the respective track instruments. Release of relay 5TR also closes back contact 5TR59 and completes an energizing circuit for control relay SR of the time measuring means. This circuit comprises the elements, battery terminal B, back contact 5TR69, front contact BPR'H], front contact BR'H, front contact CR'I2, front contact DR'l3, back contact BSR14, check contact 28-29, winding of relay SR, and C battery terminal. Relay SR pi ks up and closes at its front contact M a shunt path around the check contact 2825 and contact BSR'M, and completes at its front contact 42 the operating circuit for the relay TR. Prior to arrival of the train at location BT, relay TR completes its operation and picks up relay TPSR since the section AT--BT is 1170 feet and the train is operating at only 36.6 feet per second and requires something over 15 seconds in passing through that section. When the train arrives at location BT and operates the track instrument RI, the stick circuit for relay BR is opened and that relay is deenergized and releases to open front contact BRH interposed in the energizing circuit of relay SR and relays SR and TR are reset to their normal positions. Repeater relay BPR is also deenergized in response to the release of relay BR and releases at the end of its slow release period. During the interval relay BPR is up and relay ER is down, relay TPSR is retained energized by its stick circuit which includes front contact BPR'IB and back contact BR15 as will be understood by an inspection of Fig. 2. When relay BPR releases and opens front contact BPRIG, the relay TPSR is deenergized and releases at the end of its slow release period, the two relays BPR and TPSR being thus released in sequence.

Release of the repeater relay BPR also opens front contact BPR18 and closes the corresponding back contact 19. The opening of front contact BPR'IB discontinues the supply of current to winding 3 of relay XR over the normal energizing circuit of that winding, but winding 3 is supplied with current over its branch path which includes front contact 45 of relay TPSR and the front contact DR8I. The closing of back contact 79 of relay BPR completes a second energizing circuit for the control relay SR and which circuit comprises the elements, B battery terminal, front contact 45, front contact CR'H, back contact 19, back contact 80, front contact CR'l2, front contact DR13, back contact BSR'M, check contact 28-29, winding of relay SR, and C battery terminal. Hence, relay SR is reenergized and picked up to close the shunt path around the check contacts 28-29 and BSR'M, and to reenergize the slow acting relay TR to start a second operation of that relay. Subsequent to the release of relay TPSR, the winding 3 of relay XR is supplied with current over the branch path which includes front contact 52 of relay SR.

Relay TR completes its second operation and again picks up the relay TPSR prior to the arrival of the train at location CT since the track section BT-CT is 680 feet in length and the train 0on sumes something over 15 seconds in passing therethrough. When the train arrives at location C'I and operates track instrument R2, the stick circuit for relay GR is opened and that relay is released and opens at its front contact CRT! the second energizing circuit for relay SR with the result that relays SR and TR are again restored to their normal positions. This time relay TPSR is retained energized over a stickcircuit which includes front contact BSR82 and back contact CR83, since the relay BSR is picked up during the interval the train is passing through the section BT-CT. With relay TPSR thus retained energized'winding 3 is supplied with 0111'- rent during the time the train is advancing through the section CTDT. When the train arrives at location DI and operates track instrument R3 the relay DR is deenergized and releases to open front contact DRBI interposed in the circuit for the winding 3. Hence, winding 3 is deenergized and operation of the highway crossing signals is initiated in response to the train entering the section DTET and a warning period of substantially 30 seconds prior to the arrival of the train at the intersection is efiected. Release of relay DR also opens front contact DR84 interposed in the stick circuit for relay TPSR and that relay is restored. to its normal position. When the train passes over the intersection and to the right of location ET, the relay 5TR is reenergized andthe apparatus is restored to its normal position, that is, to the position illustrated in Fig. 2. V V

Fro-m the foregoing, it is apparent that the apparatus of Fig. 2 operates for a train traveling at the maximum speed of 80 miles per hour and for all train speeds between the maximum and minimum speed in a manner similar to the apparatus of Fig. 1 and it is thought that the operathe signals are set into operation when the train enters the section DTE.T and operates track instrument R3. As a matter of fact, for trains For train For train speeds between 31.2 and the minimum speed of 25 miles,

operating at a speed less than the assumed mini- 0 mum speed, the highway crossing signals are set into operation in response to operation of the track instrument R3.

Relay BSR functions in a manner similar to relay 38B of Fig. 1. train is traveling through the timing sections AT-BT and the relay TPSR has been picked up, and the circuit for the relay CR is interrupted accidentally, the release of relay CR to In the case a medium speed 7 close back contact CR83 is ineffective to retain relay TPS R energized over its stick circuit, since front contact BSR82 is not closed until after the relay TPSR is released.

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, a highway crossing signal located at the intersection; time measuring means including a control relay, a slow pickup relay and including a back contact of the track relay for the first section and a front contact of the track relay for the second section, an operating circuit for the slow pickup relay including a front contact of the control relay, a pickup circuit for the slow release relay including a front contact of the slow pickup relay, a stick circuit for the slow re lease relay including a back contact of the track relay of the second section and a front contact of said repeater relay, a second pickup circuit for the control relay including a front contact of the slow release relay and a back contact of said repeater relay as well as a front contact of the track relay of the third section, and circuit means for governing the operation of said signal including a front contact of the control relay and a front contact of the slow release relay in multiple.

2. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located at the intersection, two consecutive timing track sections to one side of the highway, a normally energized trafiic controlled relay for each section which becomes deenergized in response to a train entering the section, a slow acting repeater relay for the traffic controlled relay of the section nearer the highway; time measuring means including a control relay, a slow pickup relay and a slow release relay; a first energizing circuit for the control relay including a vback contact of the traffic controlled relay of the more remote section and a front contact of the trafiic controlled relay of the nearer section, an operating circuit for the slow pickup relay including a front contact of the control relay, a pickup circuit for the slow release relay including a front contact of the slow pickup relay, a stick circuit for the slow release relay including a front contact of said repeater relay and a back contact of the traffic controlled relay of the nearer section, a second energizing circuit for the control relay including a back contact of the repeater relay in series with a front contact of the slow release relay and a front contact of the control relay in multiple, and control circuit means for governing the operation of the signal comprising a main path including a front contact of the repeater relay and a branch path including a front contact of said control relay.

3. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located at the intersection, two consecutive timing track sections to one side of the highway, a normally energized traftlc controlled relay for each section which becomes deenergized inresponse to a train entering the section, a slow acting repeater relay for the traffic controlled relay of the section nearer the highway; time measuring means including a control relay, a slow pickup relay and a slow release relay; a first energizing circuit for the control relay including a back contact of the traflic controlled relay of the more remote section and a front contact of the traffic controlled relay of the nearer section, an operating circuit for the slow pickup relay including a front contact of the control relay, a pickup circuit for the slow release relay including a front contact of the slow pickup relay, a stick circuit for the slow release relay including a front contact of said repeater relay and a back contact of the trafiic controlled relay of the nearer section, a second energizing circuit for the control relay including a back contact of the repeater relay in series with a front contact of the slow release relay and a front contact of the control relay in multiple, and control circuit means for governing the operation of the signal comprising a main path including a front contact of the repeater relay and two branch paths in multiple one of which includes a front contact of the slow release relay and the other one of which includes a'front contact of the control relay.

4. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located at the intersection, two consecutive timing track sections to one side of the highway, a normally energized traffic controlled relay for each section which becomes deenergized in response to a train entering the section, a slow release repeater relay for the traffic controlled relay of the section nearer the highway; a time measuring means including a control relay, a slow acting relay, and a slow release relay; a first en ergizing circuit for the control relay including a back contact of the traffic controlled relay for the section more remote from the highway and a front contact of the trafiic controlled relay for the section nearer the highway, an operating circuit for the slow acting relay including a contact operated by the control relay, a pickup circuit for the slow release relay including a contact operated by the slow acting relay in a predetermined time interval, a stick circuit for the slow release relay including a back contact of the trailic controlled relay for the nearer section and a front contact of the repeater relay, a second energizing circuit for the control relay including a back contact of the repeater relay in series with a front contact of the slow release relay and a front contact of the control relay in multiple, and control circuit means for governing the operation of the signal comprising a main path including a front contact of the repeater relay and a branch path including a front contact of the control relay.

5. In combination, a stretch of railway track intersected by a highway, a highway crossing sig nal located at the intersection, a timing section and a first and a second operating section arranged in the order named to one side of the highway, a normally energized track relay for each section which becomes deenergized in re sponse to a train entering the section, a time measuring means including a slow acting relay and a stick relay, control means for operating said slow acting relay including a back contact of the track relay of the timing section and a front con tact of the track relay of the first operating sec tion, a pickup circuit for the stick relay including a contact operated by the slow acting relay in a predetermined time interval, a stick circuit for said stick relay including a back contact of the track relay of the first operating section, and control circuit means for governing the operation of the signal comprising a main path including a front contact of the track relay of the first operating section and a branch path including a front contact of the stick relay and a front contact of the track relay of the second operating section in series.

6. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located at the intersection; a first, a second, a third, and a fourth track section arranged to one side of the intersection; a normally energized track relay for each track section which becomes deenergized in response to a train entering the including a front contact of the slow pickup re- 7g;

lay, a first stick circuit for the slow releaserelay including a back contact of the track relay of the second section and a front contact of the repeater relay, a second energizing circuit for said control relay including a front contact of the slow release relay and a back contact of the repeater relay, a stick circuit for the control relay including a front contact of the track relay of the third section, a second stick circuit for the slow release relay including a back contact of the track relay for the third section and a front contact of the: track relay for the fourth section, and control circuit means for governing the operation of said signal comprising a main path including a front contact of the track relay for the second section and two branch paths one of which includes a front contact of the slow release relay and the other of which includes a front contact of the control relay.

7. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located at the intersection, a normally deenergized slow pickup relay, a normally deenergized slow release relay, a control relay; a first, a second, a third, and a fourth track section to one side of the intersection; a track relay for each section which becomes deenergized in response to a train entering the section, means including a back contact of the track relay for the first section to energize the control relay, means including a front contact of the control relay to energize the slow pickup relay, means including a front contact of the slow pickup relay to energize the slow release relay, means controlled by the track relay of the second section and including a front contact of the slow release relay to release and reenergize the control relay for releasing and reenergizing the slow pickup relay in response to a train passing from the first section into the second section, a stick circuit for said slow release relay including a back contact of the track relay for the third section, means including a winding effective when deenergized to operate the signal, a first control circuit to ener gize said winding including a front contact of the track relay of the second section, and other control means to energize said winding including front contact of the track relay of the fourth section in series with front contacts of the control relay and slow release relay in parallel.

8. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located at the intersection, a first, a second, and a third track section to one side of the intersection, a traffic controlled relay for each section which becomes deenergized in response to a train entering the section, a first slow release relay energized over a front contact of the traffic controlled relay of the second section, a control relay, a slow pickup relay energized over a front contact of the control relay, a second slow release relay energized over a front contact of the slow pickup relay, means including a back contact of the trafiic controlled relay of the first section and a front contact of the traffic controlled relay of the second section to energize the control relay to operate the slow pickup relay and energize the second slow release relay when a train occupies the first section for an interval greater than the pickup period of the slow pickup relay, means controlled by the traffic controlled relay of the second section to release the first and second slow release relays in sequence and to release the control relay in response to a train entering the second section, means controlled by said slow release relays to reenergize the control 9. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located at the intersection; a first, a second, and a third track section to one side of the intersection, a traffic controlled relay for each section which becomes deenergized in response to a train entering the section, a first slow release relay energized over a front contact of the trafiic controlled relay of the second section, an electroresponsive time measuring device including a check contact closed only in the normal position of said device, a second slow release relay energized over a contact of said device closed only after the device is energized a predetermined time period, means controlled over a back contact of the traffic controlled relay of the first section to energize said device to pick up the second slow release relay when a train occupies the first section for an interval greater than said time period, means controlled by the trafiic'controlled relay of the second section to release the first and second slow release relays in sequence and to deenergize said device in response to a train enteringthe second section, means controlled by said slow release relays and including said check contact to initiate a second energization of the time measuring device to again pick upthe second slow release relay when a train occupies the second section for an interval greater than said time period, a stick circuit for said second slow release relay including a back contact of the traffic controlled relay of the third section, and means including a front contact of the second slow release relay for governing the operation of the signal.

10. In combination, a first and a second consecutive track section, a normally energized traffic controlled relay for each section which becomes deenergized when a train enters the section, a normally deenergized slow pickup relay, circuit means for energizing the slow pickup relay and including a back contact of the traffic controlled relay of the first section and a front contact of the traific controlled relay of the second section, a stick circuit for the slow pickup relay including a back contact of the traffic controlled relay of the second section, a slow release stick relay, time measuring means controlled over a back contact of the traffic controlled relay of the first section and a front contact of traffic controlled relay of the second section effective to energize said slow release relay when operated a predetermined time interval, a stick circuit for said slow release relay including a back contact of the trafiic controlled relay of the second section and a front contact of the slow pickup relay, and signal control means including a front contact of said slow release relay.

11. In combination; a stretch of railway track formed into a first, a second, and a third consecutive track section; a normally energized trafiic controlled relay for each section which becomes deenergized when a train enters the section, time measuring means including a stick relay which becomes energized a predetermined time interval after said time measuring means is set into operation, means including a back contact of the traffic controlled relay of the first section and a front contact of the trafii'c controlled relay of the second section to set the time measuring means into operation, a signal, control means including a front contact of the traffic controlled relay of the third section for governing the operation of the signal, means including a front contact of said stick relay to render said control means ineffective to govern the operation of the signal, a stick circuit for the stick relay including a back contact of the trafiic controlled relay of the third section, a normally deenergized slow pickup relay, a pickup circuit for the slow pickup relay including a back contact of the traffic controlled relay of the second section and a front contact of the traffic controlled relay of the third section, a stick circuit for said slow pickup relay including a back contact of the traflic controlled relay of the third section, and a front contact of said slow pickup relay interposed in said stick circuit of the stick relay whereby accidental deenergizing of the traffic controlled relay of the third section is ineffective to retain the stick relay picked up.

12. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located at the intersection; a first, a second, and a third track section to one side of the intersection, a normally energized track relay for each section which becomes deenergized when a train enters the section, time measuring means including a contact which becomes closed a predetermined time interval after said measuring means becomes energized, means including a back contact of the track relay of the first section to energize the measuring means to close its contact when a train consumes more than said time interval in advancing through the first section, control means including a front contact of each of the track relays of thev second and third sections for operating said signal, means including the contact of said measuring means when closed to render said control means ineffective to operate the signal, stick circuit means including a back contact of the track relay of the third section eiiective to retain the contact of said measuring means closed, a slow pickup relay, a pickup circuit for said slow pickup relay including a back contact of the track relay of the second section and a front contact of the track relay of the 'third section, and a front contact of said slow pickup relay interposed in said stick circuit means whereby deenergization of the track relay of the third section while a train is approaching in either the first or the second section annuls the control of the time measuring means over the signal.

13. In combination, a stretch of railway track which is formed into a single insulated track section, a track circuit including a track relay for the section, a highway intersecting said section adjacent the exit end, a highway crossing signal located at the intersection, three track instruments located at selected points to cooperate with the track circuit to form said insulated track section into four control track sections, a traffic controlled relay associated with each track instrument which becomes deenergized in response to a train passing the instrument and becomes energized when the track relay of the insulated track section is picked up, a single electroresponsive time measuring means, circuit means controlled by said track relay and said trafiic controlled relays to associate successively the time measuring means with the first and second control track sections encountered in approaching the highway, operating means controlled by the trafiic controlled relays of the second and third control track sections to operate the signal, means controlled by the time measuring means to render at times said operating means inefiective to operate the signal, and means controlled by the traffic controlled relay of the final control track section encountered in approaching the highway to cause said operating means to operate the signal irrespective of the time measuring means.

14. In combination, a stretch of railway track formed into a single insulated track section which is intersected by a highway at its exit end, a track circuit for said section including a track relay, a highway crossing signal at the intersection; a first, a second and a third track instrument placed at selected locations to cooperate with the track circuit to form said section into four consecutive contro1 sections; said instruments each including a contact adapted to be actuated by a train, an electroresponsive time measuring means, circuit means controlled jointly by said track relay and said first track instrument to associate successively the time measuring means with the first and second control sections encountered by a train approaching the highway, operating means controlled by the first and second track instrument to operate the signal, means controlled by the time asuring means to render at times said operating means ineffective to operate the signal, and other means controlled by the third track instrument to cause said operating means to operate the signal.

15. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located at the intersection, three track instruments placed at selected locations to one side of the intersection, a time measuring means having a predetermined operating period, circuit means controlled by a train approaching the most remote instrument ,to operate the time measuring means, other circuit means governed by the most remote instrument to reset and initiate a second operation of the time measuring means in response to the train reaching the location of that instrument, means controlled by the next instrument encountered by the train to stop the operation of the time measuring means, operating means governed by the most remote instrument and by the next instrument encountered by the train to operate the signal, means governed by the time measuring means when it has completed its operation to render said operating means inefiective to operate the signal, and other means controlled by the track instrument nearest to the intersection to cause said operating means to operate the signal.

ARTHUR E. DODD. HENRY S. YOUNG.

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