US2106683A - Highway crossing signaling system - Google Patents

Description

Jan. 25, 1938. J. E. WILLING v -HIGHWA CROSSING SIGNALING SYSTEM Filed Feb. 28, 1936 INVENTO BY i MTbNEY Patented Jan. 25, 1938 UNITED STATES PATENT OFFICE General Railway Signal Company,

Rochester,

Application February 28, 1936, Serial No. 66,233

6 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 application of Mackey Ser. No.

66,232 filed February 28, 1936 and the later filed applications of Reichard Ser. N 0. 74,924 filed April 17, 1936, and Field and Willing Ser. No. 66,422 filed February 29, 1936, and no claim is made herein to anything disclosed in said Mackey, Reichard or Field and Willing applications.

It is proposed in accordance with the present invention to provide a signaling system for protecting highway traflic crossing railroads, wherein the speed of a train approaching the highway determines the point at which the highway warning is started to thereby provide a warning for a substantially uniform 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, a first section being employed to detect train speeds whereby a condition of certain controlling apparatus is established in accordance with train speeds within different predetermined limits, thus dividing all train movements into a pluraltiy of different classes according to their speed. It is then proposed to control the highway warning signal in accordance with the condition of the controlling apparatus thus established in such a manner that trains in different speed classes start the highway warning upon entering different sections whereby trains in all speed classes may arrive at the highway a substantially uniform time after the warning has been started.

Other objects of the present invention include the provision of such a highway signaling system wherein a failure of the control apparatus to properly return to a normal condition upon the completion of a train movement results in the display of a restrictive railway signal indication, whereby to indicate to a train subsequently approaching the highway that the apparatus is not functioning properly and allowing such precaution to be taken as will prevent an accident until the system can be restored to its normal operating condition.

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

A portion of a railway track having an indicated direction of traffic from left to rightis illus trated as crossing a highway represented by HW in the drawing. The portion of the railway to the left of highway HW, or the approach portion is divided into track sections I through 4 by insulating joints J, each section having the usual track circuit comprising a battery B (with corresponding exponent) and a track relay T (also with corresponding exponent).

A normally energized highway signal controlling relay CG is provided which may govern the operation of any desired type of warning device at highway HW such as flashing light signals, bells, crossing gates or the like, but for simplicity the relay CG has herein been shown as controlling the energization of a signal lamp HG. The signal I-IG is shown as deenergized in accordance with the energization of relay CG over an obvious circuit including front contacts 8, 3 and In of track relays T T and T respectively, and relay CG may also be energized by auxiliary circuits controlled in accordance with train speeds as detected in track sectionl.

The diiferent train speeds are detected in section I in the present embodiment by two timing devices ITD and ZTD with respective stick re peating relays IS and 2S. The timing devices I TD and 2TD may be of various types, but have herein been shown diagrammatically as thermal relays which may, for example, be constructed as shown in Patent No. 1,902,793 granted to J. E. Willing, March 21, 1933.

The first section is employed as a timing section or that is, the timing devices I TD and ZTD are conditioned during the length of time required by' various trains to traverse section I, which time is a measure of the train speed. In other words, when a train enters section I a circuit is completed from the terminal of a suitable source of energy, through back contact l2 of relay T front contact I3 of relay T back contact I4 of relay IS, through heating element I5 of thermal relay ITD and through a variable resistor I6, to It will be clear that the above circuit is completed only during the time in which a train is traversing section I as the entrance of the train into section 2 drops relay' '1 to open the circuit at front contact I3, and consequently the length of time in which a circuit is completed through back contact I2 and front contact I3 of track relays T and T respectively is inversely proportional to the speed of a train traversing section I.

The variable resistor I6 of thermal relay ITD may now be adjusted so that the time required by a train to traverse section I at a certain intermediate rate of speed is just sufficient for actuating member I8 of thermal relay ITD to engage a movable contact I9 with a-fixed contact 20 thereby picking up relay IS over an obvious circuit. In this manner a high speed train can traverse section I without picking up relay IS while all slower speed trains will cause relay IS to pick up, and the picking up of relay IS deenergizes the heating element I5 of relay ITD at back contact I4 and completes an energizing circuit for relay 2TD from back contact I2 of relay T front contact I3 of relay T front contact I4 of relay IS, back contact 22 of relay,

28, through heating element 23 and through a variable resistor 24, to

In this manner the slower speed trains consume a time in traversing section I which is longer than that required to operate thermal relay ITD, and the variable resistor 24 of relay 2TD may now be adjusted so that this additional time required by trains below a certain slow rate of speed is just sufficient for actuating element 26 to engage movable contact 21 with a fixed contact 28 thereby energizing relay 28 over an obvious circuit. Intermediate speed trains then traverse section I in a time sufficient to pick up relay I8 but insufficient to pick up relay 2S while slow speed trains consume a longer time in traversing section I which is sufficient to pick up both relays IS and 2S.

Relays ITD and 2TD with their repeating relays IS and 28 then comprise a speed responsive organization when controlled in this manner by the occupancy of section I, whereby all train movements are divided into three classes by the condition of these relays established according to the time required by a train to traverse section I. In other words, high speed trains do not pick up either relay IS or 2S, intermediate speed trains pick up relay IS only, while slow speed trains pick up both relays IS and 28. This speed responsive means is now employed to select which one of sections 2, 3 or 4 is to start the warning at highway HW, or that is, high speed trains are to start the warning upon entering section 2, intermediate speed trains upon entering section 3 and slow speed trains upon entering section 4.

A high speed train as previously described traverses section I in a time insuflicient to pick up either relay IS or 28 and consequently upon entering section 2, this high speed train deenergizes the control relay CG at front contact 8 of relay T and the warning signal I-IG is energized through back contact 30 of relay CG. This energizing circuit for relay CG is maintained open until the train has passed the highway I-IW by open front contacts 9 and ID of relay T and T respectively.

An intermediate speed train, however, in traversing section I picks up relay IS which is held up as long as section I or section 2 is occupied over a stick circuit including its front contact 32 and multiple back contacts 33 and 34 of relays T and '1 respectively. This intermediate speed train does not deenergize relay CG upon entering section 2 as it may be seen on the accompanying drawing that a front contact 35 of relay IS shunts around front contact 8 of relay '1 in a manner to maintain relay CG energized after relay I drops, or that is, relay CG is then energized over a circuit including front contact 35 of relay IS, front contact 9 of relay T and front contact II] of relay TH This intermediate speed train then starts the warning upon entering section 3 by deenergizing relay CG at front contact 9 of relay T and thereafter maintains the warning upon entering section 4 by holding relay CG deenergized at front contact ID of relay T A slow speed train as previously described picks up both relays IS and 2S while traversing section I, relay 2S being held up while sections I, 2 and 3 are occupied by a stick circuit including its front contact 31 and a front contact 38 of relay IS in multiple with a back contact 39 of relay T Consequently relay CG is maintained energized while this slow speed train traverses section 2 and section 3 over a circuit including front contact 40 of relay 2S and front contact II] of relay T which circuit obviously is opened when this slow speed train enters section 4 at front contact III of relay T thereby starting the warning at this point.

In this manner the system can be so organized that the maximum speed train which starts the warning upon entering each of the sections 2,3 and 4 will reach the highway I-IW only after a period of time which is considered to be the time necessary to warn highway traflic prior to the actual arrival of the train. In other words, the distance traveled by the maximum speed train in the required warning time should bethe distance from the entrance end of section 2 to the highway, the distance traveled by an intermediate speed train in the same time should be the distance from the entrance end of section 3 to the highway, and likewise the distance traveled by a slow speed train in this same time shouldbe the distance from the entranceend of section 4 to the highway.

During the time in which a slower speed train occupied section I, the thermal relays ITD and 2TD are operated as previously described to pick up the respective stick relays IS and 28, whereupon the heating elements of the thermal relays are-deenergized by contacts of the stick relays, the stick relays being held up by their stick circuits until the train has started the highway warning signal as previously described. However, in the event the actuating element of either of the thermal relays fails to properly return to its normal position after the completion of a train movement, it will be clear that the operating time of the' thermal relay would be considerably reduced which might permit a high speed train to establish a condition of the relays IS and 2S ordinarily corresponding to a slow speed move- -ment. Such a conditionwould of course withhold the warning at the highway until the high speed train had reached section 3 or 4 so that a warning time for a dangerously short period would result.

In order to prevent such a dangerous condition from arising due to the failure of the thermal relays ITD and 2'I'D to be in their normal positions when a train enters section I, it is contemplated to indicate such an abnormal condition to an approaching train whereby the trainspeed may be reduced or extra precautions may be taken which are unnecessary during normal operation of the highway signaling system.

The illustrated means for providing such a check on the normal position of the thermal relays comprises contacts -45 on the thermal relay I'I'D andsimilarcontacts 48'49 on relay 2TD, which contacts are only closed when the respective actuating elements I8 and Marc in their normal positions; These contacts +45 and 48-49 are indicatedasiincluded.intseries with-the ener izin circuit 50 of the usual home control relay H which is indicated diagrammatically as controlling a wayside railway signal RG by Contact 52 in'the usual manner. "The home relay H is normally energized asshown to provide a clear or proceed signal indication in accordance with forward traflic conditions, and it will then beclear that this relay H will be deenergized by contacts 4445 or contacts 48-49 to provide a restrictive signal indication unless the actuating .elements or relays ITD and 2TD are both in their normal deenergized positions.

A highway signaling system is thus provided wherein a plurality of time responsive means are distinctively conditioned in accordance with the time required for trains 'to traverse a first track section, whereby the condition of these timing means selects which one of several other track sections will be effective to control the starting of the highway warning. The control track sections are located at different distances from the highway, and a section is then selected by the condition of the time responsive means which is located a distance from the highway proportional to the train speed, thus permitting all trains regardless of size variations in speed to arrive at the highway a substantially uniform time after the warning has been started. The present system also checks the proper return of the time responsive means to a normal condition at the completion of a train movement whereby to restrict railway traffic until a normal condition is restored, thereby permitting the engineer of an approaching train to proceed with such precaution as will supplement any insufiicient automatic warning which may result from this improper condition of the time responsive means. 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 construction or the various organizations or combinations that may be employed. For example, the present system is not limited to the use of two timing devices as shown but could be organized in a very similar manner with a different number of timing devices whereby to divide train movements into a larger or a smaller number of speed classes with the number of controlling track sections provided to correspond therewith. It is also to be understood that various timing devices other than thermal relays could also be employed. In other words, the particular embodiment of the present invention has been selected to facili tate in the disclosure thereof rather than to limit the number of forms which it may assume.

What I claim is:

1. In a signaling system for highway crossings on railroads, a plurality of track sections occupied successively by a train approaching the high- Way, a track circuit including a track relay for each section, a first slow acting device controlled by a back contact of a first track relay and a front contact of a second track relay in series, a first repeating relay controlled by the first slow acting device, a stick circuit for the first repeating relay controlled by multiple back contacts of the first and second track relays, a second slow acting device controlled by a back contact of the first track relay, a front contact of the second track relay and a front contact of the first repeating relay, a second repeating relay controlled by the second slow acting device, a stick circuit for the second repeating relay controlled by a front contact of the first repeating relay in multiple with a back contact of a third track relay, a highway crossing signal, and means'starting operation of the signal when a train approaching the highway enters the secondor the third or a fourth track section in accordance with the condition of the first and second repeating relays.

2. In a signaling system for highway crossings on railroads, a plurality of track sections occupied successively by a train approaching the highway, a track circuit including a track relay for each section, a first slow acting device controlled by a back contact of a first track relay and a front contact of a second track relay in series, a first repeating relay controlled by the first slow acting device, a stick circuit for the first repeat ing relay controlled by multiple back contacts of the first and second track relays, a second slow acting device controlledby' a back-contact of the first track relay, a front'contact of the second track relay and a front contact of the first repeating relay, a second repeating relay controlled by the second slow acting device, a stick circuit for the second repeating relay controlled by a front contact of the first repeating relay in multiple with a back contact of a third track relay, a highway crossing signal, and means starting operation of the signal when a train approaching the highway enters the second or the third or a fourth track section according as the first and the second repeating relays are de-energized or the first repeating relay only is energized or the second repeating relay is energized.

3. In a signaling system for highway crossings on railroads, a plurality of track sections occupied successively by a train approaching the highway, a first thermal relay set into operation when a train enters the first of the track sections, a first stick relay energized by a complete opera.- tion of the first thermal relay, a second thermal relay set into operation when the first stick relay is energized while a train occupies the first track section, a second stick relay energized by a complete operation of the second thermal relay, a normally energized signal control relay at the highway, and means for de-energizing the signal control relay When a train enters the second or the third or the fourth track sections, respectively, according as the first and the second stick relays are de-energized or the first stick relay only is energized or the second stick relay is energized.

4. In a signaling system for highway crossings on railroads, a plurality of track sections occupied successively by a train approaching the highway, a first thermal relay set into operation when a train enters the first of the track sections, a first stick relay energized by a complete operation of the first thermal relay, a second thermal relay set into operation when the first stick relay is energized while a train occupies the first track section, a second stick relay energized by a complete operation of the second thermal relay, a normally energized highway signal control relay, means for de-energizing the signal control relay when a train enters the second or the third or the fourth track sections according as the first and the second stickrelays are deenergized or the first stick relay only is energized or the second stick relay is energized, a signal governing train movements toward the highway, and means controlling the signal in accordance with the condition of the first and the second thermal relays.

5. In combination, a portion of railway track intersected by a highway and divided into four sections traversed successively by a train approaching the highway, a track circuit including a track relay for each section, a highway signal for the intersection, two thermal relays arranged in cascade and serially energizable through a back contact of the first track relay and a front contact of the second track relay in series, and two stick relays wholly separate from said thermal relays and distinctively conditioned in accordance with the complete operation of the thermal relays respectively for selectively starting operation of the highway signal upon entrance of a train into the second or the third or the fourth track sections.

6. In combination, a portion of railway track intersected by a highway and divided into four sections traversed successively by a train appreaching the highway, a track circuit including a track relay for each section, a highway signal for the intersection, two thermalrelays serially energizable through a back contact of the first track relay and a front contact of the second track relay in series, two stick relays wholly separate from the thermal relays and distinctively conditioned in accordance with the complete operation of neither, or one only, or of both of the thermal relays for selectively starting operation of the highway signal upon entrance of a train into the second or the third or the fourth track sections, respectively, a railway signal governing train movements approaching the highway, and control means for the railway signal including contacts of the two thermal relays in series, said contacts being closed only when the thermal relays are in their normal de-energized positions.

JOSEPH E. WILLING.

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