US1926789A

US1926789A - Railway traffic controlling apparatus

Info

Publication number: US1926789A
Application number: US438995A
Authority: US
Inventors: Melvin A Penrod
Original assignee: Union Switch and Signal Inc
Current assignee: Hitachi Rail STS USA Inc
Priority date: 1930-03-26
Filing date: 1930-03-26
Publication date: 1933-09-12
Anticipated expiration: 1950-09-12

Description

war/v M. A. PENROD S 14 [Jr- 27 (20:50 JECT/O/V T0 1?! orpouvrp OCC'UP/ED.

INVENTORZ M H Pe nro Original Filed March 26 Fig]. 20

Si 0 w RAILWAY TRAFFIC CONTROLLING APPARATUS Sept. 12, 1933.

Patented Sept. 12, 1933 RAILWAY TRAFFIC CONTROLLING APPARATUS Melvin A. Penrod, Murrysville, Pa., assignor' to The Union Switch& Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application 11 Claims.

My invention relates to railway traffic controlling apparatus, and particularly to apparatus for controlling traffic'governing devices, such as railway track switches, by levers which are located at a central point such as an interlocking tower.

One feature of my invention is the provision of means for controlling the movement of a switch in accordance with traffic conditions in advance of the switch.

I will describe two forms of apparatus embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawing, Fig. 1 is a diagrammatic view illustrating. one form of apparatus embodying my invention. Fig. 2 is a similar view showing a modified form of a'portion of the apparatus of Fig. 1, and also embodying my invention.

Similar reference characters refer to similar parts in both views.

Referring first to Fig. 1 of the drawing, the reference characters land 1 designate the track rails of a stretch of railway track X, which is divided, by means of insulated joints 2, into a plurality of track. sections Al3, B0 and CD. A second track Y is connected with the track X by means of a switch G located in section B-C, and the rails 1 and 1 thereof are divided, by

insulated joints 3, to form a section E- -F. Each of thesections A B, B-C, CD and is provided with a track circuit which is supplied with current by a track battery 4 connected across the rails adjacent one end of the section, and

which includes a track relay, designated by the reference character R having a distinguishing exponent corresponding to its location, connected across the rails adjacent the opposite end of the section. The section of the track Y between the point F and the switch G is included in the track circuit of the section BC by a conductor 5 connectingthe rails 1 and l 'of the tracksX and Y, respectively.

The entrance of a westbound train into the section C-D is controlled by a signal S and by an automatic train stopping device 6, and its movement over the switch G is controlled by signals S and S In a like manner the movementof 5 a westbound train from the section 'A-B of the main track X or from the section E-F of, the track Y is controlled by signals S and S re.- spectively. Also, the movement of an eastbound trainover the switch G from the section A B of the track X'or from'the section EF of the March-26, 1930, Serial No. 438,995 Renewed June 8, 1932 track Y is controlled by the usual dwarf signals S and S respectively.

Switch G is controlled by an operating mechanism J which is in turn controlled by a manually operable lever v 'which is located at a remote 6Q point,-such as an interlocking tower, and which is movable between a normal position 12, indicated by full lines in the drawing, and a reverse position r, indicated by broken lines in this view. The lever V operates an arm 7 which engages a contact '7" when the lever occupies its normal or 12 position and a contact 7 when the lever occupies its reverse or 1' position. The lever V also operates an arm 8 which engages a contact 8" when the lever occupies its normal or n position and a contact 8 when the lever occupies its reverse or 7' position. By means of this lever the towerman may operate the mechanism J so as to move the switch G between its normal and reverse position. Under certain trackway conditions, hereinafter to be described, the lever V will be locked in its normal position by a latch 9 00- operating with a locking segment 10 and under certain other trackway conditions this lever will be locked in its reverse. position by a latch 11 Q cooperating with a locking segment 12. The

segments

10 and 12 are both mounted on the same shaft on which the lever ,V is mounted, which shaft may constitute part of an interlocking mas chine of the usual type, and the

latches

9 and 11 are operated to engage and disengage the segments by a lock magnet Lwhich is controlled by a control relay K.

The signal S and. the train stopping device 6 are controlled by a lever V which may be located in the interlocking tower, through. the medium of a relay T, and also by a circuit controller H comprising a contact 13-14 closed at all times except when the switch G occupies its reverse position, and a contact 13-15 closed at all times except when the switch occupies its normal position. The lever V moves between a normal position 11 and a reverse position 2' and operates a contact 16, a contact 17 and a slowacting contact l8. When the lever V occupies m0 its normal position 41, in which it is illustrated in the drawing, contact 16 is open, the contact 17 is closed, and the slow-acting contact l8 is also closed. When, however, the lever V is moved to its reverse position 1*, contact 16 is closed, and contacts 17 and 18 are opened. The slow-acting contact 18 is of the type that opens quickly when the lever V is moved to its reverse position but requires a predetermined interval of time after the lever V is returned to its normal position before this contact is closed. One form of device which may be used to operate this contact is disclosed in Letters Patent of the United States No. 1,157,960, granted to H. 13. Post on October 26, 1915. When levers V and V both occupy their n positions and relay R is energized, the control relay K is energized by current traversing three different circuits thereby maintaining its

contacts

19 and 20 closed. Current in the first of these circuits flows from terminal a: of a suitable source of electrical energy not shown in the drawing, through contact 8-8 of lever V front contact 21 of track relay R and winding of relay K to the other terminal 0 of the same source. Current in the secondof these circuits flows from terminal as, through slow-acting contact 18 of lever V and winding of relay K to terminal 0. The third circuit is a stick circuit for the control relay K through which current fiows from terminal a", through contact 17 of lever V contact 19 of control relay K, and the winding of this relay to terminal 0. As hereinbefore mentioned, the energization of the relay K maintains the contact 20 thereof closed, and consequently the lock magnet L will be energized by current flowing from terminal 0:, through a front contact 22 of track relay R contact 20 of control relay K, and winding of lock magnet L to terminal 0. The energization of magnet L maintains the

latches

9 and 11 out of engagement with the

segments

10 and 12, thereby permitting operation of the switchlever V to its reverse position should the towerman desire to reverse the switch G.

I will now assume that the towerman desires to move the signal S to its clear position, and the automatic train stopping device 6 to an ineffective position in order to allow a westbound through train to pass over the track X. Under such circumstances he swings the signal lever V to the right, as viewed in Fig. l, to its reverse position 1", thereby opening the contacts 1'? and 18 and closing the contact 16. The opening of the contacts 1'7 and 18 breaks the circuits through these contacts which energized the relay K jointly with the circuit through the contact 8-8 of the lever V but inasmuch as contact 8---8 of lever V is closed, the circuit for relay K through this contact remains closed and as a consequence the relay K remains energized. The closing of the contact 16 by the above-described movement of the leverV establishes a circuit from the terminal a: through contact 16 of lever V front contact 23 of track relay R contact l .-13 of circuit controller H, front contact 24 of track relay R front contact 25 of track relay R and winding. of relay T to terminal 0. The current in this circuit energizes the relay T and causes it to close its

front contacts

26 and 27 and establish two separate circuits Current in the first of these circuits flows from terminal as, through contact 26 of relay T, and the operating mechanism of signal S to terminal 0, thereby causing the signal S to assume its clear position; The current in the second of these circuits flows from terminal m, through contact 2'? of relay T and the mechanism of the automatic train stopping device 6 to terminal 0, and causes the device 6 to assume its ineifective position.

As the train enters the section CD from the east the track relay R is deenergized, thereby releasing its front contact 25, and breaking the circuit previously traced through the relay T thus causing this relay to become deenergized. This causes the signal S to again display a stop indication to succeeding trains. The deenerg'ization of track relay R also causes a contact 28 thereof to close and to establish a circuit from terminal x, through back contact 28 of track relay R contact 29, and operating mechanism of the automatic train stopping device 6 to terminal 0. Contact 29 is closed when the section to the right of point D is occupied, and the circuit just traced therefore prevents device 6 from resuming its normal effective position while the train'is passing over it, that is, while the train occupies both section CD and the section to the rightof this section.

As soon as the train enters section B-'-C, the track relay It becomes deenergized and opens its front contacts22 and 24. The opening of the contact 22 breaks the circuit previously traced, which maintains the lock magnet L energized and causesthe release of the

latches

9 and 11. The notch in the segment 10, being in registry with the latch 9 at this time is engaged thereby and prevents theleverman from operating the lever V to reverse the switch G while the train is passing over the switch and as long as it occupies'the section 'B-C.

When the train leaves section CD the track relay R becomes reenergized and closes its contact 25 but by reason of the fact that the contact 24 of relay R is now open the circuit through the relay T remains open and the signal S continues to display'a stop indication. The energization of track relay R also opens its contact 28 thereby opening the circuit previously traced through this contact and the contact 29 which maintains the automatic train stopping device 6 ineffective and permits this device to resume itsnormal active position for succeeding trains.

As soon as the train enters section A-B the track relay R becomes deenergized, and opens its front contact 23, thereby creating another break in the circuit of the signal control relay T previously traced through this contact. As a result the signal relay T will not become energized by the closing of contact 24 when the track relay R becomes energized upon the departure of the train from section B-C. The signal S thereforecontinues to display a stop indication. When the train leaves section BC, the energization of track relay R causes its front contact 22 to close, thereby reestabling the circuit through the lock magnet L. This causes the latch 9 to move out of engagement with the segment 10 so as to. permit the leverman to move the switch G to its reverse position if he so desires.

' As soon as the train passes out of section A-B, the track relay R again becomes energized and closes its front contact 23, thereby completing the circuit through the signal relay T and causing it to close its

contacts

26 and 27. This will again complete the circuits controlling the signal S and the train stopping device 6 and cause the former to display a clear indication and the latter to assume its ineffective position.

If, now, the towerman swings the lever V back to its normal position n the contact 16 operated thereby will open and break the circuit therethrough which caused the energization of the signal relay T. The

contacts

26 and 27 of the relay T will therefore again open and break the circuits therethrough. This will cause the signal S to display a stop indication and the train stopping device to assume its normal active position. The system is now in its initial condition, as shown'in Fig. 1.

I will nowassume that the towerman desires to route a westbound trainifrom the track X to the track Y. He, therefore, swings the switch lever V to the right to its 1 position, thereby opening the contact '7-7 and closing the contact '77 The closing of contact '7--7 causes the energization of the switch operating-mechanism J and moves the switch G to its reverse position. The above described movement of the lever V also opens the contact 88"' and closes the contact 88 The opening or" the contact 8S breaks the circuit through this contact, the contact 21 of track R and the winding of relay K, but the stick circuit through the contact 17 of lever V and the circuit through the slow-acting contact 18 remain intact, so that relay K remains energized. The closing of the contact 8-8 establishes an additional circuit for the relay K through front contact 30 of track relay R The movement of the switch G from its normal to its reverse position opens contact 1314 and closes contact 1315 of the circuit controller l-I. p

The towerman now swings thelever V to its reverse or 1' position thereby closing its contact 16 and opening both of its other contacts 17 and 18. The closing of contact 16 establishes a circuit from terminal a: through contact 16 of lever V front contact 31 of track relay R contact 1315 of circuit controller, front contact 24 of trackrelay R front contact 25 of track relay R and winding of relay T to terminal 0. The energization of this relay closes its contacts 26 and 2'7 and causes the signal S to display a clear indication and the automatic train stopping device 6 to assume an ineifective position as hereinbefore described. The opening of contacts 17 and 18 of lever V breaks the circuits through these contacts which energizes the control relay K leaving this relay energized by. the additional circuit hereinbefore traced through the contact 8-8 1 of lever V and front contact 30 of track relay R When a westbound train enters section C-D the track relay R becomes deenergized. This opens front contact 25, and deenergizes relay- T with the result that the

contacts

26 and 27 thereof open and interrupt the circuits therethroughr The result of this is that the signal S is caused to again display a stop indication but the train stopping device 6 is maintained in its ineffective position by the circuit through back contact 28 of relay R and contact 29.

Upon the entry of the train into section 3-0 the track relay R becomes deenergized and opens its front contacts 24 and 22. The opening of contact 22 causes deenergization of lock relay L and permits its latch 11 to move into locking engagement with the associated segment 12, thereby preventing the switch lever V from being operated to return the switch G to normal as long as any portion of the train occupies section B C. As the train departs from section CD the track relay R again becomes energized and closes its front contact 25 and opens its back contact 28, but by reason of the fact that the contact 24 ofthe track relay R is open, the circuit through the relay T is held open. The opening of the contact 28 breaks the circuit that holds the device 6 ineffective and therefore this device resumes its normal operative position for succeeding trains.

The train next proceeds over the switch G and enters section E-F of track Y immediately c ausing the deenergization of track relay R As the train departs from section BC the track relay R again becomes energized and closes its contacts 24 and 22 but inasmuchas the front contact 31 of relay R is now open, the circuit for relayT is held open. The signal S therefore remains at stop. The closing of contact 22 of track relay R however, reestablishes the circuit through the lock magnet L and causes it to move the latch 11 out of engagement with the segment 12. lever V may now be operated to return the switch to normal if so desired.

It will be noted that the switch lever V is locked against movement so that it is impossible to return the switch G to its normal position, as long i the switch G- from being moved from normal to reverse after a westbound train has entered section CD upon a clear? indication of the signal S and the possibility of derailment occa sioned thereby. For example, I will assume that section EF of track Y is occupied by a west- The bound train and that the switch G has been re- 7 turned to its normal position and the signal 5 displays a clear indication for westbound trafiic 7 yer track X. Under these conditions I will also assume that another westbound train enters section C-D and that the towerman desires for some reason to switch the second train onto the track Y occupi d by the first train. The switch 1 G is however locked in its normal position by reason of the fact that the contacts l7, 19, 18 and 21, which independently control the energization of lock magnet L are all open. The towerman can not close contact 21 because the track relay R which controls this contact is deenergized due to the presence of the first train in section EF. He

can not cause the energization of the lock magnet L by closing contact 17 because the contact 19 J in this stick circuit is open due to the deenergization of the magnet K. The towerman, therefore, must first return the signal lever V to its normal position thereby releasing the slow-closing contact 18. The time interval of this contact is of sufficient duration to permit the second train to 1 pass the switch entirely if it is a fast moving train that does not have time to stop before crossing the switch or if although having sufficient time to stop, disregards the signal. The time interval is,

however, of suificient duration to permit the train to come to a complete stop before it reaches the switch G if the engineer of the westbound train 7 obeys the signal S and is not running at too great a speed. If the second train stops before reaching the switch G the circuit through con: 5

tact 18 will be established at the expiration of the time interval and the control relay K will be energized and close contact 20, thereby causing the energization of the lock magnet L, as previously described. This will cause the release of the switch lever V and permit the towerman to move the switch G to its reverse position. The second train may then proceed onto the track Y at reduced speed.

I will now assume that an eastbound train, is

approaching section E-F oftrack Y and that the switch G- occupies its normal position and that the signal S displays a clear indication for west-v bound trains over the track X. Under such conit ons ihece i l e av is ne 'siz n b current in the circuit controlled by contact 21 of track relay R and contact 8-8 of switch lever V Consequently, if the eastbound train should enter section E-F before the towerman reverses the switch G, the track relay R already having become deenergized and opened its front contact 21, relay K will have become deenergized and opened its front contact 20, thereby deenergizing the lock magnet L and preventing the subsequent operation of the switch lever V Also, if the towerman should first move the signal lever V to its normal position in order to cause the signal S to display a stop indication to westbound traffic, the slow-acting contact 18 might not close before the eastbound train enters section EF. As a result the control relay K would become deenergized and cause the switch lever V to be locked in its normal position as above described.

I avoid the above mentioned difficulty by the provision of the stick circuit controlled by the contact 17 of the signal lever V and the contact 19 of the control relay K. By means of this circuit the towerman can prevent the deenergization of the relay K if he moves the signal lever V to it normal position and thereby closes the contact 17, while the relay K is still energized by current traversing the circuit controlled by the

contacts

7 and 21. If the eastbound train new enters section E F anddeenergizes the track relay R the control relay K will notbecome deenergized through the delayed closing of slowacting contact 18. The switch lever V is therefore maintained in an unlocked condition thereby permitting the towerman to move the switch G to normal at his convenience.

In Figure 2 I have shown another form of my invention for delaying the energization of the control relay K and the unlocking of the switch G when it is desired to reverse the switch while the section E-F is occupied. In'this arrangement the slow-acting contact 18 shown in Fig. 1 is omitted and a contact 32 operated by a slow pick-up relay M substituted therefor. The relay M is controlled by a contact 33 operated by track relay R and is provided with a second contact 34 which is closed only when the relay M is de energized and which is interposed in the signal circuit between the circuit controller 5 and the contact 24 of track relay B In all other particulars the arrangement shown'in Fig; 2 is the same as that disclosed in Fig. land therefore much of the corresponding apparatus has been omitted from the drawing. With the arrangement above described I will again assume that the section E-F is occupied, that the switch G is in its normal position, and that the signal S displays a clear indication to westbound traffic over track X.

If a westbound train now enters section C-D the track relay R will become deenergized and open its front contact 25, thereby breaking the signal circuit and causing the signal S to display a stop indication to succeeding trains, as hereinbefore described. The deenergization of track relay R also closes its back contact 33, thereby completing a circuit from terminal a: through contact 33 and winding of slow pick-up relay M to terminal 0. This causes the energization of slow pick-up relay M but by reason of its slow-acting characteristics it will not close its contact 32 until the expiration of a predetermined time interval; As a result, the circuit through this contact 32 which controls the energization of control relay K is notimmediately established and the contact 20 controlled by this relay remains open. This prevents the immediate energization of the lock relay L and maintains the switch G locked in its normal position until the expiration of the time interval required for the slow pick-up relay M to close its contact 32. in the system shown in Fig. 1, this time interval is of sufiicient duration to permit the westbound train to pass entirely over the switch G before the switch actuating mechanism is unlocked, thereby eliminating the danger of moving the switch beneath the train in the event that the towerman. should make a sudden decision to reverse the switch without giving the train sufficient time to stop or in the event that the train should disregard the signal and proceed over the switch.

If, however, the towerman decides in due time to route the train onto track Y for some reason,

he first actuates the signals S and S by means forming no part of my present invention to indicate such fact in time to permit the train to stop before reaching the switch G. At the expiration of the time interval after deenergization of relay E above mentioned the contact 32 of the slow pick-up relay M closes, thereby completing a circuit through the control relay K. The energization of control relay K causes the contact 20 controlled thereby'to close and to complete the circuit previously traced through the lock magnet L. This causes the energization of the lock magnet and causes it to elevate the latch 9 out of engagement with its associated locking segment 10 and release the switch lever V The towerman may now operate the lever V to reverse the switch as hereinbefore described.

From the foregoing it will be apparent that I have provided a very simple and convenient apparatus for controlling the operation of a track switch in accordance with the condition of the track both in front of and beyond the switch whereby the danger of moving a switch beneath a train is to a large extent eliminated.

Although I have herein shown and described only two forms of apparatus embodying my 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 my inven tion.

Having thus described my invention, what I claim is: a

1. In combination, a plurality of tracks each divided into a plurality of sections, a track switch located in one of said sections for connecting said tracks, switch operating means for moving said switch between normal and reverse positions, a lever for controlling said operating means, lock mechanism for controlling the operation of said lever, electromagnetic means for controlling the operation of said lockinechanism, a control re lay for controlling the operation of said electromagnetic means, a first contact adapted to be closed when said lever is moved to a normal position for controlling said control relay, a second contact adapted to be closed when said lever is moved to a reverse position for controlling said control relay jointly with said first contact, a

track relay associated with one of said sections a of one of said tracks for controlling said control relay jointly with saidfirst contact, a track relay associated with one of said sections of another of said tracks for controllingsaid control relay jointly with said second contact, and means As in the case of the slow-acting contact 18 for at times controlling said control relay independently of said first and second contacts and said track relays.

2. In combination, a pluralityof tracks each divided into a plurality of sections, a track switch located in one of said sections for connecting said tracks, switch operating 'meansfor moving said switch between normal andreverse positions, a lever for controlling said operating means, lock mechanism for controlling the operation of said lever, electromagnetic means for controlling the operation of said lock mechanism, a control relay for controlling the operation of said electromagnetic means, a first contact adapted to be closed when said lever is moved to a normal position iorcontrolling said control relay, a second contact adapted to be closed when said lever is moved 'to a reverse position for controllingsaid control relay jointly with said first contact, a track relay associated with one of said sections of one of said tracks for controlling said control relay jointly with. said first contact, a track relay associated with one of said sections of another of said tracks for controlling said control relay jointly with said second contact, and a stick circuit including a third contact for at times controlling said control relay independently of said first and second contacts and said track relays.

3. In combination, a plurality of tracks each divided into a plurality of sections, a track switch located in one of said sections for connecting said tracks, switch operating means for moving said switch between normal and reverse positions, a lever for controlling said operating means, lock mechanism for controlling the operation of said lever, electromagnetic means for controlling the operation of said lock mechanism, a control relay for controllingthe operation of said electro magnetic means, a first contact adapted to be closed when said lever is moved to a normal position for controlling said control relay, a second contact adapted to be closed when saidlever is moved to a reverse position for controlling said control relay jointly witlrsaid first contact, a track relay associated withone of said sections of one of said tracks for controlling said control relay jointly with said first contact, a track relay associated with one of said sections or" another of said tracks for controlling said control'relay jointly with said second contact, a signal for controlling traffic over said tracks, signal controlling means for causing said signal to display clear and stop indications, and a third contact adapted to be operated when said signal controlling means is operated for controlling said control relay independently of said first and second contacts and said track relays.

4. In combination, a plurality of tracks each divided into a plurality of sections, a track switch located in one of said sections for connecting said tracks, switch operating means for moving said switch between normal and reverse positions, a lever for controlling said operating means, lock mechanism for controlling the operation of said lever, electromagnetic means for controlling the operation of said lockmechanism, a control relay for controlling the operation of said electromagnetic means, a first contact adapted to be closed only when said lever is moved to its normal position, a second contact adapted to be closed only when said lever is moved to its reverse position, a track relay associated with one of said sections of one of said tracks on one side of said switch, a second track relay associated with another of said sections of-auother of said tracks on the same side of said switch, a first control circuit including said first contact and a front contact or" said first track relay for controlling said control relay, a second control circuit including said second contact and a front contact of said second track relay for controlling said control relay, and a slow-acting contact for at times controlling said control relay independently of said first and second control circuits.

5. In combination, a plurality of tracks each divided into a plurality of sections, a track switch located one of said sections for connecting said tracks, switch operating means for moving said switch between normal and reverse positions, a lever for controlling said operating means, lock mechanism for controlling the operation of said lever, electromagnetic means for controlling the operation of said lock mechanism, a control relay for controlling the operation of said electromagnetic means, a first contact adapted to be closed only when said lever is moved to its normal position, a second contact adapted to be closed only when said lever is moved to its reverse position,

a track relay associated with one of said sections 1 of one of said tracks on one side of said switch, a second track relay associated with another 01 said sections of another of said tracks on the same side of said switch, a first control circuit including said first contact and a front contact 1 of said first track relay for controlling said control relay, a second control circuit including said second contact and a front contact of said second track relay for controlling said control relay, a signal for indicating the condition of said 1 tracks, signal controlling means for causing said signal to display clear and stop indications, and a slow-acting contact operated by said signal controlling means for controlling said control relay independently of said first and second con- 1 trol circuits.

6. In combination, a plurality of tracks each divided'into a plurality of sections, a track switch located in one of said sections for connecting, said tracks, switch operating means for moving said 1 switch between normal and reverse positions, a lever for controlling said operating means, lock mechanism for controlling the operation of said lever, electromagnetic means for controlling the operation of said lock mechanism, a control relay 1 for controlling the operation of said electromagnetic means, a first contactto be closed only when said lever is moved to its normal position, a second contact adapted to be closed only when said lever is moved to its reverse position, a track relay associated with one of said sections of one of said tracks on one side of said switch, a second track relay associated with another of said sections of another of said tracks on the same side I of said switch, a first control circuit including 1 said first contact and a front contact of said first track relay for controlling said control relay, a second control circuit including said second contact and a front contact. of said second track relay for controlling said control relay, a 3, signal for indicating the condition of said'tracks, signal controlling means for causing said signal to display clear and stop indications, and a slow-acting contact adapted to be closed when said signal controlling means is actuated to cause said signal to display a stop indication for controlling said control relay independently of said first and second control circuits,

, '7. In combination, a railway track, a second railway track, a track switch connecting said 1 second track with said first track and which in its normal position directs trafiic movements along said first track only but which in its reverse position directs traiiic movements along said first track to or from said second track, a signal for governing trains approaching said switch in the facing direction, a circuit controlled by said switch'in its normal position and by traflic conditions on said first track beyond said switch for controlling said signal, a second circuit controlled by said switch in its reverse position and by traffic conditions on said second track for controlling said signal, and means for preventing an operation of said switch from one oi its positions to the other while said signal is controlled to indicate proceed if trafiic conditions on that track beyond the switch to which traffic would be directed by such operation of the switch are such as to cause said signal to indicate stop.

8. In combination, a railway track, a second railway track, a track switch connecting said second track with said first track and which in its normal position directs traffic movements along said first track only but which in its reverse position directs trafiic movements along said first track to or from said second track, a signal for governing trains approaching said switch in the facing direction, a circuit controlled by said switch in its normal position and by traffic conditions on said first track beyond said switch for controlling said signal, a second circuit controlled by said switch in its reverse positicn and by traflic conditions on said second track for controlling said signal, and means for delaying for a measured period of time an operation of said switch from one of its positions to the other if trafiic conditions on that track beyond the switch to which traffic would be directed by such operation of the switch are such as to cause said signal to indicate stop.

9. In combination, a stretch of railway track comprising a switch section and a second section, a second stretch of track including a third section, a switch in said switch section connecting said second stretch with said first stretch, a switch lever having a normal and a reverse contact closed in normal and reverse positions respectively of said lever, means controlled by said leverfor operating said switch to its normal position for directing trafiic movements along said first stretch only or to its reverse position for directing trafiic movements to or from said sec ond stretch according as said lever is placed in its normal or its reverse position respectively, a locking relay, a circuit controlled by said normal lever contact and by traffic conditions in said third section for controlling said relay, a second circuit controlled by said reverse lever contact and by trafiic conditions in said second section for controlling said relay, a manually controllable slow-acting device, a third circuit controlled by said slow-acting device for controlling said relay, and meanscontrolled by said relay for controlling said lever.

10. In combination, a stretch of railway track comprising a switch section and a second section, a second stretch of track including a third section, a switch in said switch section connecting said second stretch with said first j stretch, a switch lever having a normal and a reverse contact closed in normal and reverse positions respectively of said lever, means controlled by said lever for operating said switch to its normal position for directing trafiic movements along said first stretch only or to its reverse position for directing trafiic movements to or from said second stretch according as said lever is placed in its normal or its reverse position respectively, a locking relay, a circuit controlled by said normal lever contact and by traffic conditions in said third section for controlling said relay, a second circuit controlled by said reverse lever contact and by traific conditions in said second section for controlling said relay, a slow-acting device controlled by traffic conditions in said first stretch in the direction from said switch from which trains approach when facing said switch, a third circuit controlled by said slow-acting device for controlling said relay, and means controlled by said relay for controlling said lever.

11. In combination, a stretch of railway track comprising a switch section and a second section, a second stretch of track includinga third section, a switch in said switch section connecting said second stretch with said first stretch, a switch lever having a normal and a reverse con tact closed in normal and reverse positions respectively of said lever, means controlled by said lever for operating said switch to its normal position for directing trafiic movements along said first stretch only 01' to its reverse position for directing trafiic movements to or from said second stretch according as said lever is placed in its normal or its reverse position respectively, a locking relay, a circuit controlled by said normal lever contact and by traffic conditions in said third section for controlling said relay, a second circuit controlled by said reverse lever contact and by trafiic conditions in said second section for controlling said relay, a signal for governing traffic movements toward said switch in the facing direction, a signal lever having a normal and a reverse position and having a first contact which is closed if and only if its lever is in the reverse position and a second contact which is closed if and only if its lever is in the normal position as well as a third contact which becomes closed if and only if its lever has been in the normal position a measured period or" time, a third circuit controlled by the third contact of said signal lever for controlling said relay, a stick circuit for controlling said relay controlled by the second contact of said signal lever, a circuit controlled by the first contact of said signal lever and by traffic conditions in said second section for controlling said signal if said switch is in its normal position, a circuit controlled by the first contact of said signal lever and by traffic conditions in said third section for controlling said signal if said switch is in its reverse position, and means-controlled by said relay for controlling said switch lever.

MELVIN A. PENROD.