US2106681A - Highway crossing signaling system - Google Patents

Description

W- INVENTOR 77L ATTOR NEY S. J. MACKEY I Filed Feb. 28, 1936 HIGHWAY CROSSING SIGNALING SYSTEM Jan. 25, 1938.

Patented Jan. 25, 1938 mater PATENT oF ics HIGHWAY CROSSING SIGNALING SYSTEM Stuart J. Mackey, Rochester, N. Y., assignor to General Railway Signal Company, Rochester,

Application February 28, 1936, Serial No. 66,232

7 Claims.

This invention relates in general to signaling systems, and more particularly to a Signaling system for highway crossings on railroads, which invention is of later origin than the invention disclosed in the later filed application of Reichard Ser. No. 74,924 filed April 17, 1936, and no claim is made herein to anything disclosed in said later filed Reichard application.

It is proposed, in accordance with the present invention, to provide a signaling system for protecting highway trafiic crossing railroads, wherein the speed of a train approaching the highway determines the point at which the highway warning is initiated to thereby always provide a warning for a substantially constant time prior to the actual arrival of the train at the highway.

More specifically, it is proposed to provide a plurality'of track sections in the railroad approaching the highway crossing, each section having a timing means responsive to speed in the associated section above a critical value, and wherein a different critical speed is assigned to the timing means of each section according to the distance of the section from the crossing. It is then proposed to employ these timing means in the control of highway signals in a manner causing different speed trains to initiate the highway warning upon entering different sections, whereby each train, regardless of its speed, may arrive at the crossing a substantially constant time after the warning has been initiated.

Other objects of the present invention include the provision of such a highway signaling system wherein a failure of any circuit, source of energy, or apparatus employed in the control of the highway signals, to properly respond, results in an immediate display of a warning indication at the highway, thus preventing such a failure from causing an unsafe condition, and serving to direct attention to the fact that this abnormal condition exists.

Still other objects, purposes and characteristic features of the present invention will be obvious as the description thereof progresses, during which reference will be made to the accompanying drawing which illustrates, in a diagrammatic and conventional manner, one specific embodiment of the present invention in Fig. 1; and another specific embodiment in Fig. 2.

Referring to Fig. 1; a portion of a railway track, having an indicated direction of traffic from left to right, is illustrated as crossing a highway H, in the drawing. The approach portion of the highway, or portion to the left of highway H, is divided into track sections I through 5, each section having the usual track circuit comprising a battery B, (with corresponding exponent), and a track relay T, (also with corresponding exponent).

In this embodiment of the invention, the track sections are all of the same length, but ,as will be later described, in connection with Fig. 2, these sections can be of different lengths. A timing device is employed at each of the track sections I, 2 and 3, which timing device has, for convenience, been shown as a slow releasing relay TS, (with an exponent correspondingto theassociated section), but it is understood that various other well known types of electrically controlled timing means could be used, In the illustrated form of the present invention, wherein all the track sections are of the same length, these timing devices must have different operating times, that is, relay T8 must be slower to release than relay TS and relay TS- must be slower to release than relay TS The slow releasing relays TS have two windings, the lower or pick up windings of all three relays being normally energized in multiple over a circuit from of a suitable source'of energy, through front contacts in, H, l2, l3 and M of track relays T T T T and T respec: tively, and through their respective lowerwind ings to The upper windings of these slow releasing relays'TS are alsonormally energized over individual stick circuitsincluding their own front contacts and a front contact of the associated track relay, as, for example, the upper. winding of relay TS is energized from (-1-), through front contact l8 of relay T jstick contact [9, through its upper winding to the upper winding of relay T8 is energized from front contact 20 of relay T stick contact 2|, through its upper winding to and the upper winding of relay TS is energized from (-5-), through front contact 22 of relay T stick contact 23, through its upper winding, to

A signal control relay CR is provided at the highway H, which relay is also provided with both a pick up and a stick winding, the upper or pick up winding being normally energized over a circuit from through the same series of contacts In, H, l2, l3 and M of the track relays. and also through front contacts 25, 2B and' 2lof the slow releasing relays TS TS and T5 and through its upper winding to The stick or lower winding of relay CR is also normally energized over a circuit from (-1-), front contact 30 of relay T front contact 3! of relay T front contact'32 of relay T front contact 33 of relay T stick contact 34, and through its lower winding, to

In this stick circuit for relay CR, a multiple path is provided around each of the front contacts 3i], 3! and 32 of track relays T T and T which multiple circuit includes a back contact of the slow releasing relay TS which is associated with the respective rear adjacent track section. In other words, front contact 30 of relay T may be shunted by back contact 36 of relay T8 front contact 3| of relay T may be shunted by back contact 31 of relay T8 and front contact 32 of relay T may be shunted by back contact 38 of relay T8 The control relay CR may govern the opera-v tion of any desired warning device at highway H, such as flashing light signals, bells, crossing gates or the like, but forsimplicity the relay CR. has herein been shown as controlling the energization of a signal lamp G through a back contact 40.

When the apparatus of the present system is in its illustrated, or normal, condition, it will be clear that a train approaching highway H, successively drops track relays T "T T T and T thereby initially opening the energizing circuit for the pick up windings of relays TS T8 TS and CR at front contact I41 of relay T and thereafter retaining these pick up circuits open at one or more of contacts I3, I 2 or II. It will then be clear that the holding up of timing relays TS and the control relay OR is dependent on their respective stick circuits during this train movement.

When a train enters section l the dropping of relay T opens the stick circuit for relay T8 at front contact I 8, and the track section I is of such a length that a train traveling above a certain high rate of speed traverses this distance to enter section 2 and drop relay T before relay TS releases its armature. In other words, the length of time required for relay TS to release its armature after deenergization must be so proportioned to the length of section I that such a high speed train drops relay T before the timing relay TS releases its armature, thereby opening the stick circuit for relay OR. at contact 39, before the multiple circuit through contact 36 is closed. 3

It will then be clear that when the stick circuit for relay CR is thus opened by front contact 39 before back contact 36 closes, the armature of relay CR is released to open itsfront contact 34 whereby subsequent closing of back contact 35 cannot pick up relay CR. A warning is then given athighway H by energizing signal G through back contact 40 of relay CR when this high speed train enters section. 2, which warning obviously continues due to the sustained deenergization of relay CR. until the train clears the highway H, whereupon the system is restored to its normal illustrated condition in a manner to be later described in detail.

In organizing the track circuits of the present system, various factors of warning time and maximum speed must necessarily be considered, and it is believed that the various relations of these factors in organizing any system will be apparent if one method of organizing the system is explained with assumed values for these factors. I

It will first be clear that the insulating joints separating sections l and 2 must be located such a distance from the highway that a train traveling at the maximum speed reaches the highway from this point after a period of time which is considered to give the necessary warning time to highway traflic prior to the actual arrival of the train. In other words, if it is considered adequate to warn highway traffic for 20 seconds prior to the actual arrival of a train, it is necessary that a maximum speed train consume 20 seconds in reaching the highway after entering section 2. Consequently if 'the maximum speed attained by trains in this portion of the system is 60 miles per hour, or 88 feet per second, such a train consumes 20 seconds in traveling 1760 feet, which should be the distance from the entrance end of section 2 to the highway.

The system, in its illustrated form, Fig. 1, using three timing devices, and five sections, contemplates the distinction between four classes of trains according to their speed. Consequently, if the track sections are to be of equal lengths, these speed classes must be evenly divided, such as a high speed class between 60 and 45 miles per hour, an intermediate speed class below 45 and including 30 miles per hour, a normal slow speed class below 30 and including 15 miles per hour,

and a fourth class including all speeds below 15 miles per hour.

The length of each section is accordingly determined, whereby, if the distance from the entrance end of section 2 to the highway is 1760 feet, which distance is to be divided into four equal length track sections, the length of each of the five sections must be 440 feet. According to the present assumed speed classes, all trains traveling at or above 45 miles per hour must start the warning upon entering section 2 and i consequently the releasing time of relay TS must be 6% seconds or slightly less to allow a train traveling at or above 45 miles per hour or 66 feet per second to traversethe 440 foot length of section 1 before the armature of relay TS is released.

-It will then be clear that all trains traveling slower than 45 miles per hour will consume sufficient time in traversing section i, for relay TS to have released its armature before such train enters section 2, thereby allowing back contact 36 to have closed before front contact 30 opens, which retains energy on the stick circuit for relay CR, and prevents initiation of the warning signal G at this point.

When a train enters section 2, the second timing relay TS is deenergized at front contact 26, and the releasing time of this relay T5 is so chosen that all trains traveling slower than 30 miles per hour will consume sufficient time in traversing section 2, for relay T5 to have released, before the train has entered section 3. Consequently the releasing time of relay T8 must be 10 seconds or slightly less to cause a train traveling at or faster than 30 miles per hour, or 44 feet per second, to traverse the 440 foot distance of section 2 before the armature of TS is released.

In this manner, all trains at or above this 30 mile per hour rate, traverse section 2 in, or less than, 10 seconds, to enter section 3 and open front contact 3i before relay T5 releases its armature to close back contact 31, thereby opening the stick circuit for relay CR and initiating the warning signal G upon the train entering section 3. According to the assumed speed classes, the maximum speed train which thus starts the warning upon entering section 3 is just below 45 miles per hour, or 66 feet per sec- 0nd, and as the distance from the entrance end of section 3, to the highway, is the combined lengths of sections 3, 4 and 5, or 1320 feet, a train in this intermediate speed class cannot reach the highway without providing at least the requisite 20 second warning time.

When a train enters section 3, the third timing relay TS is deenergized at front contact 22, and the releasing time of this relay T8 is so chosen that all trains traveling at or over miles per hour, traverse section 3 before the armature of relay T8 is released. Consequently the releasing time of relay T8 must be .20 seconds or slightly less, to allow a train traveling at or faster than 15 miles per hour or 22 feet per second, to traverse the 440 foot length of section 3 before the armature of T5 is released.

In this manner, all trains as or above this 15 mile per hour rate, traverse section 3 in or less than, seconds, to enter section 4, and open contact 32 of track relay T before relay TS releases its armature to close back contact 38, thereby opening the stick circuit for relay CR and initiating the warning signal G upon entering section 4. Also, according to the assuming speed classes, the maximum speed train which thus starts the warning upon entering section 4 is just below 30 miles per hour, or 44 feet per second, and as the distance from the entrance end of section 3 to the highway is the combined lengths of sections 4 and 5 or 880 feet, a train in this slow speed class cannot reach the highway without providing at least the 20 second warning time.

It will then be clear that all trains traveling slower than 15 miles per hour, will consume sufficient time in traversing section 3 for relay T8 to have released its armature before such train can enter section 2, thereby allowing back con- I tact 38 to have closed before front contact 32 has opened, which retains energy on the stick circuit for relay CR, and prevents energization of the warning signal at this point.

However when any train traveling below this 15 mile per hour rate enters section 5, the stick circuit for relay CR is positively opened at front contact 33 thereby energizing the warning signal G upon entering section 5. Inasmuch as the maximum speed train starting the warning in this manner upon entering section 5 is below 15 miles per hour, or 22 feet per second, and as the length of section 5 is 440 feet, all trains below this 15 mile per hour rate provide at least the 20 second warning time before reaching the highway.

In this manner a highway signaling system has been provided wherein a plurality of timing means, each distinctively related to an associated track section, are arranged in a manner toeach respond to train speeds in an associated section above different predetermined values, thus dividing all train movements into a. plurality of speed classes wherein trains in different speed classes start the highway warning upon entering different track sections. The track sections are then so arranged that the entrance end of each section is such a distance from the highway that the maximum speed train which starts the warning upon entering this section cannot reach the highway in less than the length of time necessary to warn highway trafiic. In this manner, a train, regardless of its speed, cannot reach the crossing before a warning is given for at least the predetermined length of time, and yet the warning cannot be given for an excessively long period of time. In'other words, the warning time is constant regardless of the speed of trains approaching the highway except for the small variations due to the range of speeds within each speed class.

When a train movement has been completed across the highway to clear section 5, the multiple pick up circuits for the timing relays TS T8 and TS are completed through front contacts I0, H, I2, l3, and M of the track relays and as soon as the timing relays all pickup to close contacts 25, 26, and 21, the pick up circuit for the control relay CR. is completed, thereby restoring the system to its normal illustrated condition.

However, in the event one or more of the timing relays TS fails to pick up upon the completion of a train movement, the control relay CR obviously cannot be energized, thereby maintaining an indication of warning at the highway which prevents a subsequent train movement from reaching the crossing without properly warning highway traffic, as would occur in the event relay CR could pick up with one or more of the timing relays TS deenergized. In this manner, the control relay CR cannot be energized to discontinue the warning indication until all the other relays of the system have properly picked up, thereby preventing a dangerous condition from arising-dueto a. failure of any of the apparatus to return to its normal condition, by retaining an indication which may be unduly restrictive to highway traffic but thereby serves to direct attention to the existence of an abnormal condition.

Referring now to Fig. 2; the system there illustrated accomplishes the same results as that of Fig. 1; but instead of using'sections of equal length, and timing relays of differing release times; there are here used timing relays of the same release value, and sections of differing lengths.

In this form, the approaching train controls the track relays, and they. in turn control the timing relays, which in turn control the signal control relay and the signal, by circuits identical with those shown in Fig. 1, and hence no further description is considered necessary for a complete'disclosure of this form.

One specific form of this embodiment maybe organized with the three timing relays each having 40 second release value, and the track sections, five in number, may be divided up of lengths 1760 feet, 880 feet, 440 feet, 220feet and 220 feet respectively as one approaches the cross ing. Consequently, a train approaching the crossing at 30 miles per hour and up to 60 miles per hour, initiates the signal at the entrance to section 2 and one at a speed of from 15 miles per hour up to 30 miles per hour, initiates the signal at the entrance to section 3 and one at a speed of from 7 miles per hour up to 15 miles per hour initiates the signal at the entrance to section 4 and all slower speed trains initiate the signal at the entrance to section 5 This arrangement then clearly operates in the same manner as the form shown in Fig. 1, that is, a time is initiated, and the time the train arrives at the crossing regardless of the speed of the train.

In this system, a following train is fully protected, since such train prevents the reenergization of the control relay CR, due to one or more of the track relays being down until the following train has cleared the crossing.

Furthermore, should a train, upon approaching the crossing, come to a stop before the signal has been initiated, the signal will not be initiated, re-

gardless of how long the train so remains, thus avoiding the delays usual in other systems due to trains standing on an approach section; Of course, if the signal is once initiated, it will continue in operation until all the track relays and all the timing relays have picked up; that is, until the train either has cleared the. crossing or has backed out of the control sections.

This system is also of advantage, inasmuch as it is in accordance with a usual practice of a train, on approaching a crossing, to progressively decelerate, and thus a signal is not initiated by the train when proceeding at a fast speed when at a distance from the crossing, and then be continued an undue time prior to the arrival of the train because the train has subsequently reduced its speed.

In describing the present invention, attention has been directed to one specific embodiment thereof without attempting to point out the various alternate or optional features of construc-- tion, or the different organizations or combinations that may be employed,

However, it may be generally stated that in organizing the present system, the relation between the maximum speeds starting the warning at sections 2, 3 and 4 must be the same as the relation between the lengths of sections 2, 3 and 4 in order to provide a distance from each starting point of the warning to the crossing which a train at the particular speed can travel in not less than the predetermined warning time. The length of the last section 5 is of course only determined by the maximum speed which starts the warning at this point, while the firstsection I could be of any desired length providing the releasing time of its relay TS is accordingly selected to respond to the desired speed.

In other words, the particular embodiments of the present invention have. been selected to facilitate in the disclosure thereof rather than to limit the number of forms which it may assume, and the invention is contemplated to embrace all modifications and variations that come within the scope of the appended claims.

What I claim is:-

1. In a signaling system for highway crossings on railroads, a plurality of track circuit sections each having a normally energized track relay in the portion of the railroad traversed by trains approaching the highway, a slow releasing timing means associated with each track section, a pick up circuit for all the timing means including series front contacts of all the track relays, a stick circuit for each timing means including the front contact of its associated track relay, a highway signal controlling relay having a pick up circuit including series front contacts of all the track relays and series front contacts of all the timing means, and a stick circuit for the signal controlling relay including series front contacts of the track relays with a back contact of each timing means in multiple with the front contact of the next forward track relay.

2. In combination, in highway crossing signal systems for railways, a portion of track approaching a highway and divided into a plurality of sections, a warning signal, and means responsive to a train traversing each section above a speed predetermined for that section, for setting the signal into operation upon entrance to the next section in approaching the highway and for continuing the signal operation uninterruptedly until the train reaches the crossing, each section comprising a track circuit, and a timing relay for each section, distinctively timed relatively to the length of its section, with the relative timing different for each section, the timing means for each section cooperating with the track relay of the next forward section, for causing said setting of the signal into operation.

3. In combination, in a crossing signal for railways, a stretch of track intersected by a highway, a signal at the highway, a local source of energy at the highway, a signal control relay at the highway, means dividing the stretch up into a plurality of insulated sections, and means at a plurality of the sections, measuring from the crossing, respectively responsive to a different traversing train speed in the section immediately to the rear thereof, for causing operation of the control relay upon occupancy of the immediately adjacent forward section to connect the local source to the signal and maintain it so connected uninterruptedly until the train reaches the crossing.

4- In a signaling system for highway crossings on railroads, a plurality of track circuit sections each having a normally energized track relay in the portion of the railroad traversed by trains approaching the highway, a slow releasing timing means associated with each track section, a pick up circuit for all the timing means including series front contacts of all the track relays, a stick circuit for each timing means including the front contact of its associated track relay, a signal at the highway, a local source of energy at the highway, a highway signal controlling relay at the highway and having a pick up circuit including series front contacts of all the track relays and series front contacts of all the timing means, a stick circuit for the signal controlling relay ineluding series front contacts of the track relays withv a back contact of each timing means in multiple with the front contact of the next forward track relay, and means controlled by the signal relay for connecting the signal to said local source.

5. In a signaling system for highway-railway crossings, in combination, a plurality of insulated track sections each having a normally energized relay in the portion of railroad traversed by trains approaching the highway, a slow acting timing means associated with each of the sections, a control circuit for each timing means in-- cluding a front contact of a track relay, a stick circuit for each timing means including the front contact of its associated track relay, a signal control relay having a pick up circuit including a front contact of a track relay and series front contacts of all the timing means, and a stick circuit for the signal control relay including a track relay front contact with a back contact of each timing means in multiple with the front contact of the next forward track relay.

6. In a highway crossing signal system, in combination, a signal, a signal control relay operable to control the signal, a plurality of insulated track sections approaching a highway each having a track relay, a timing means associated with each track section, means whereby each timing means is initiated by its track relay to close a contact a predetermined time after initiation, and a circuit for the signal control relay including series front contacts of the track relays with a contact of each timing means in multiple with the next forward track relay contact.

'7. In a highway crossing signal system, in combination. a signal. a signal control relay operable to control the signal, a plurality of insulated track sections approaching a highway each having a track relay, a timing means associated with each track section, means whereby each timing means is initiated by its track relay to close a contact a predetermined time after initiation, and a stick circuit for the signal control relay including series front contacts of the track relays with a contact of each timing means in multiple with the next forward track relay contact, and a pick up circuit for the signal control relay including series contacts of each 5 timing means and. a track relay.

STUART J. MACKEY.

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