US2184878A - Apparatus for the control of highway crossing signals - Google Patents

Description

Dec. 26, 1939. P. J. SIMMEN- APPARATUS FOR THE CONTROL OF HIGHWAY CROSSING SIGNALS Filed Feb. 18, 1938 o 4 w m g ..2 41 V MW fi n uvw P. {W 4 4%. 2 mm 24L 5 m 2 M 2 p ITOR f aul l HIS ATTORNEY Patented Dec. 26, 1939 UNITED STATES APPARATUS FOR THE CONTROL OF HIGH- WAY CROSSING SIGNALS Paul J. Simmen, Eden, N. Y., assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application February 18, 1938, Serial No. 191,213 I 3 Claims.

My invention relates to apparatus controlled by a train approaching a highway intersection for governing the operation of a highway crossing signal.

One feature of my invention is the provision of novel and improved apparatus controlled by a train approaching the highway crossing to prevent the continued operation of a highway crossing signal when the train stops within the control stretch, and to restart the operation of the signal when the train resumes its movement. Other features and advantages of my invention will appear as the description proceeds.

I shall describe one form of apparatus embodying my invention, and shall then point out the novel features thereof in claims.

For a better understanding of my invention, reference may be had to the accompanying drawing, of which Fig. 1 is a diagrammatic view showing a preferred form of apparatus embodying my invention. Fig, 2 is a view partially in section and partially diagrammatic which shows one form of a track instrument that may be used in the apparatus shown in Fig. 1. In each of the two views, similar reference characters refer to similar parts.

Referring to Fig. 1, the reference characters I and la designate the track rails of a stretch of railway track over which traflic normally moves in both directions, and which is intersected at grade by a highway H. A highway crossing signal S is located adjacent the intersection. This signal S may be of any suitable type, and as here shown is an audible signal in the form of an electric bell.

A plurality of train actuated devices or track instruments are associated with the track rails at selected points on the left-hand side of the highway as viewed in Fig. 1, only four instruments DI, D2, D3 and D4 being shown in the drawing. Each of these instruments is provided with a normally open contact which is closed only during the period that the instrument is depressed or actuated by a wheel of a moving train. That is to say, each successive wheel of a train depresses the instrument to close the contact. When the instrument is not depressed by a wheel, the instrument returns to its normal position, and the contact opens and remains open until the instrument is actuated by the next wheel. The instrument also is provided with means effective to open the contact when a wheel comes to rest upon the instrument.

One form'of a track instrument having the above characteristics is shown in Fig. 2. Referring to this view, the reference character 2 designates a tie to which rail I and the track instrument D are attached. A lever 3 is pivoted at 4 and its right end is so positioned that it is depressed by a wheel I2 of a car passing along rail I. Lever 3 is so biased that after the wheel passes off the lever 3, the lever returns to its normal position. A piston 5, which is movable in a cylinder 6, is connected by a rod 5a to the left end of lever 3. Within an extension of cylinder 6 a second piston I, operates, A rod 8 is attached to piston I and when raised, closes a contact 9I-0. Cylinder 6 also contains a small port II.

The operation of track instrument D is as follows: A car Wheel I2, moving on rail I, depresses lever 3 in passing. Piston 5 rises, compressing the air in cylinder 6, which raises piston I and closes contact 9I0. 'As soon as car wheel l2 has passed the instrument, lever 3 returns to its normal position, pistons 5 and I drop, and contact 9-) opens. If, however, a train stops so that a car wheel depresses lever 3, the air in cylinder 6 will exhaust through port II, piston I will drop, and contact 9-! will open. It is to be understood that this type of track instrument is merely given as an illustration, and that my invention is not restrictedto this one particular type shown.

The track instruments are arranged in groups of two along the stretch of track; as here shown they are in two groups, one being made up of instruments DI and D2, and the other being made up of instruments D3 and D4.

The groups of two track instruments are so spaced along the stretch of railway that a train,

' moving over the stretch, actuates thefirst track instrument D3 of the second group in something less than a predetermined period of time after the train has completely passed the first track instrument DI of the first group.

The distance between the two track instruments in each group may have any convenient value which permits the actuation of one track instrument before the actuation of the other track instrument.

The first group of track instruments encountered by a train approaching highway H is preferably located at a point distant enough from highway H to permit an adequate Warning period for signal S prior to the arrival of the train at the crossing. This location is determined by the distance that a train will travel while moving at maximum speed for the minimum period of warning. For example, assuming a maximum train Speed of miles an hour, or 88 feet per second, and a minimum warning period of 20 seconds, during which period trains will travel 1760 feet, it can be seen that under the assumed conditions the first group of track instruments should be located 1760 feet from highway H.

The group of track instruments positioned nearest the highway H is located at a distance from the highway substantially equal to the distance that the rear end of a slow moving train (for example, a train moving at 10 miles per hour) will traverse Within a selected period of time.

It is to be understood that although only two groups of track instruments are shown in the drawing, in actual practice there will be provided a sufficient number of such groups so that continuous operation of the signal will be effected by an eastbound train, moving from left to right in the drawing, when the train approaches and during the interval the train occupies the intersection. The spacing between each two adjacent groups of instruments will be such that the east bound train in approaching the highway will reach and actuate the first track instrument of the advance group in something less than the previously mentioned predetermined time interval after passing the first track instrument of the rear group.

Track instrument D! controls a first slow releasing relay RI provided for the first group of instruments through a circuit which passes from one terminal of battery I3 through contact 9Iil of instrument DI, winding 32 of relay Rl, and back contact M of a second slow releasing relay R2 to the other terminal of battery I3. Track instrument D2 controls slow releasing relay R2 through a circuit which passes from one terminal of battery I3 through contact I5-I6 of instrument D2, winding 33 of relay R2, and back contact I! of relay RI to the other terminal of battery I 3,

Track instrument D3 controls a first slow releasing relay R3 provided for the other groups of instruments through a circuit passing from one terminal of battery ZI through contact 2223 of instrument D3, winding of relay R3, and back contact 24 of a slow releasing relay R4 to the other terminal of battery 2i. Similarly, track instrument D4 controls slow releasing relay RA through a circuit passing from one terminal of battery 2I through contact 252-5 of instrument D4, winding of relay R4, and back contact 2'5 of relay R3 to the other terminal of battery 2I Each relay R is made slow releasing, as shown, by virtue of a dashpot I9 operatively connected with the armature of the associated relay. The dashpots I9, as will be made clear presently, will be so adjusted that each first relay of a group (except the first relay of the group nearest the highway) retains its armature in its picked-up position for the previously mentioned predetermined time interval; the first relay of the group nearest the highway retains its armature in its picked-up position for the previously mentioned selected period of time; and the second relay of each group retains its armature in its picked-up position a period of time sufiicient to permit successive actuations of the associated second track instrument by the Wheels of a slow moving train.

Signal S is provided with an operating circuit which passes from one terminal B of a source of current, such as a battery not shown, through a front contact of each first relay of a group in multiple and signal S to the other terminal C of the source of current.

The apparatus is in its normal condition when no train is Within the control stretch. In this normal condition, the contacts of the respective track instruments are open, the associated slow releasing relays are deenergized, and signal S does not operate.

In order to describe the operation of apparatus embodying my invention, I shall assume that an eastbound train approaches highway I-I. When. the train reaches track instrument DI, the first wheel of the train depresses lever 3 of that track instrument, which closes contact 9Iil and energizes relay RI. Back contact I I of relay RI opens, and front contact 58 of relay RI closes to completethe circuit for signal S, placing signal S in operation. When the first wheel of the train strikes lever 3 of track instrument D2, closing contact I5-I6, relay R2 does not become energized because its previously traced circuit is opened at back contact I! of relay RI.

The armature 28 of slow releasing relay RI is held in its energized position for the previously mentioned predetermined period of time by virtue of the adjustment of its associated dashpot I 9. This period of time is sufiicient, at least, to maintain armature 20 of relay RI in its upper position until succeeding wheels of the train actuate track instrument DI and reclose contact 3-H! to reenergize relay RI.

After the train completely passes track instrument DI, armature 2i] of relay RI resumes its lower position at the end of its release period. Within that period, however, the train reaches the first track instrument of the next adjacent group, here shown as instrument D3 of the second group of track instruments. The actuation of track instrument D3 closes its contact 2223; the energizing circuit for relay R3 is then completed, and relay R3 becomes energized so that front contact 28 of relay R3 closes to complete the circuit for signal S prior to front contact I8 of relay RI opening the circuit for signal S. Thus the train, proceeding toward highway H, successively actuates the first track instrument in each succeeding group of track instruments prior to the release of the armature and front contact of the relay controlled by a previously passed group. It follows that trains which do not stop within the control stretch operate the signal continuously, and the signal operates from the time the first wheel of the train depresses the first track instrument of the first group encountered until a selected period of time after the last wheel of the train passes the first instrument of the group nearest the intersection.

In the event the train stops within the control stretch in such a manner that the wheels of the train do not depress the track instruments, then that slow releasing relay which is controlling the circuit for signal S releases at the end of its predetermined release period, and signal S stops opera-ting. If, however, the train stops with a wheel in contact with a a track instrument, the air in the cylinder exhausts through port II as discussed before, the contact of that instrument opens, and the slow release relay governed by that contact releases to open the front contact of the relay and to stop the operation of signal S.

Then, when the train resumes its movement toward the crossing and actuates the first track instrument of a group positioned between the train and the intersection, the contact of that instrument closes to energize the first relay associated with that track instrument. The front contact of that relay closes to complete the operating circuit for signal S so that operation of way crossing through the control stretch of rail-.

way, the wheels of the train first strike the second track instrument D4 of the group positioned nearest the intersection, closing contact 25-46 of that instrument to complete the circuit for relay R4. Relay R4 becomes energized, and opens back contact 24. Then, when the wheels of the train strike track instrument D3 and close contact 22-23,'relay R3 does not become energized because its circuit is open at back contact 24 of relay R4. Front contact 28 of relay R3 consequently does not close and signal S does not operate. The dashpot I9 associated with armature 36 of slow releasing relay R4 is adjusted so that the armature is retained in its energized position for a period of time sufiicient to permit succeeding wheels of the train to actuate track instrument D4 and reclose contact 2526 to reenergize relay R4.

After the train completely passes track instrument D4, armature 20 of relay R4 resumes its lower position at the end of its slow release period. Within that period, however, the train completely passes track instrument D3 so that the latter instrument is no longer actuated and relay R3 remains released. When the train reaches the second track instrument D2 of the next group of track instruments, the actuation of that instrument closes its contact I5-I6, which completes the energizing circuit for relay R2. Relay R2 becomes energized, and opens back contact I4, so that when the train reaches track instrument DI, the closing of contact 9-H] cannot complete the circuit for relay RI. Consequently, front contact I8 of relay RI does not close, and the signal does not operate.

It is readily apparent from the foregoing that the westbound train, in receding past the intersection, successively actuates the second track instrument in each succeeding group of track instruments prior to actuating the first instrument of each group, and that the release period of the second relay of each group is such that the relay armature is held in its picked-up position until after the train completely passes the two instruments of the group. It follows that operation of the signal will not be effected by trains receding from the intersection over the railway stretch along which the track instruments are spaced.

It is to be understood that for trains approaching the intersection from the right, similar apparatus, which is not shown in Fig. 1, may be provided, and that the operation of this apparatus by a train approaching or receding from the intersection is similar to that just described.

One advantage of apparatus embodying my invention is the provision of means to terminate the operation of a highway crossing signal when a train, which has entered a control stretch and has started the signal, stops within the stretch, and to restart the operation of the signal when the train resumes its movement toward the intersection.

Although I have herein shown and described only one form of apparatus embodying my invention, it is understood that various changes andmodifications may be made-therein within the scope of the appended claims without'departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination with a stretch of railway track over which traflic moves in either direction and which is intersected at grade by a highway, a highway crossing protective signal system of the class wherein operation of a highway crossing signal is initiated by a train moving toward the intersection within a given zone adjacent the intersection and is discontinued if the train stops within said given zone and is resumed when the train resumes its movement toward the intersection, comprising in combination, a highway crossing signal positioned adjacent the intersection, a plurality of groups of two track instruments each group spaced apart along said stretch within said given zone, the track instruments of each group being spaced apart along said stretch with the first instrument of each group being positioned more remote from the intersection than the second instrument, said track instruments each having a normally open contact which is closed when and only when the instrument is actuated by a wheel of a moving train, means controlled by the first track instrument of each of the groups and effective when that instrument is the first instrument of its group to be actuated by a train for operating the signal during the interval such instrument is actuated and for a predetermined interval of time thereafter, and means controlled by the second track instrument of each group and efiective when that instrument is the first instrument of its group to be actuated by a train for preventing the other instrument of the group from operating the signal.

2. In combination with a stretch of railway track over which trafiic moves in either direction and which is intersected at grade by a highway, a highway crossing protective signal system of the class wherein operation of a highway crossing signal is initiated by a train moving toward the intersection within a given zone adjacent the intersection and is discontinued if the train stops within said given zone and is resumed when the train resumes its movement toward the intersection, comprising in combination, a highway crossing signal positioned adjacent the intersection, a plurality of groups of two track instruments each group spaced apart along said stretch within said given zone, the track instruments of each group being spaced apart along said stretch with the first instrument of each group being positioned more remote from the intersection than the second instrument, said track instruments each having a normally open contact which is closed when and only when the instrument is actuated by a wheel of a moving train, a first slow release relay and a second slow release relay for each group of track instruments, each first relay being energized solely by virtue of an energizing circuit controlled at all times by the contact of the first track instrument of the associated group and by a back contact of the associated second relay, each second relay being energized solely by virtue of an energizing circuit controlled at all times by the contact of the second track instrument of the associated group and by a back contact of the associated first relay, and an operating circuit for said signal including a front contact of each of said first relays.

3. In combination with a stretch of railway track over which traffic moves in either direction and which is intersected at grade by a highway, a highway crossing protective signal system of the class wherein operation of a highway crossing signal is initiated by a train moving toward the intersection within a given zone adjacent the intersection and is discontinued if the train stops within said given zone and is resumed when the train resumes its movement toward the intersection, comprising in combination, a highway crossing signal positioned adjacent the intersection, a plurality of groups of two track instruments each group spaced apart along said stretch within said given zone, the track instruments of each group being spaced apart along said stretch with the first instrument of each group being positioned more remote from the intersection than the second instrument, said track instruments each having a normally open contact which is closed when and only when the instrument is actuated by a wheel of a moving train, two relays for each group one for the first instrument and the second for the second instrument, energizing circuit means controlled by each track instrument of a group for energizing its associated relay, said circuit means being efiective to energize the associated relay when and only when the associated track instrument is the first of the group to be actuated by a train moving over said stretch, means governed by each first relay of a group for operating said signal, and means effective for a train moving toward the intersection and associated with each first relay of a group to maintain operation of the signal at least until the first relay of the next adjacent group is energized.

PAUL J. SIMMEN.

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