US1703128A

US1703128A - Railway signaling apparatus

Info

Publication number: US1703128A
Application number: US661671A
Authority: US
Inventors: Herbert A Wallace
Original assignee: Union Switch and Signal Inc
Current assignee: Hitachi Rail STS USA Inc
Priority date: 1923-09-08
Filing date: 1923-09-08
Publication date: 1929-02-26
Anticipated expiration: 1946-02-26

Description

Feb'.'26,' 929.

H. A. WALLACE R AILWAY SIGNALING APPARATUS 2 Sheets-Shet Original Filed Sept. 1925 We .7 A 0?..rWW

Maw/a 'Fb. 26, 1929. 1,703,128 I v H. A'. WALLACE RAILWAY SIGNALING APPARATUS Original Filed Sept. 1923' ZShets-Sheefi '2 f INVEQTQR:

M4 ATTORNEY Patented Feb, 26, 1929.

, UNITED STATES M 1,703,123 PATENT OFFICE.

HERBERT A. wALLAcE, or EDGEWOOD BOROUGH, PENNSYLVANI ASSIGNOR 'To THE UNION SWITCH & SIGNAL COMPANY, or swIssvALE, PENNSYLVANIA, A CORPO- BATION OF PENNSYLVANIA.

RAILWAY SIGNALING APPARATUS.

Application filed September 8, 1923, Serial No. 661,671. Renewed March 2, 1927.-

My invention relates to railway signaling apparatus, and particularly to apparatus of the type comprising signals controlled automatically by the passage of trains along the track.

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

In the accompanying drawings, Fig. 1 is a diagrammatic view showing one form and arrangement of railway signaling apparatus embodying my invention. Figs. 2, 3 and 4 are views showing modifications of the apparatus illustrated in Fig. 1 and also embodying my invention.

Similar reference characters refer to similar parts in each of the several views.

Referring first to Fig. 1, the

reference characters

1 and 1 designate the rails of a railroad over which traflic normally moves in the direction indicated by the arrow. These rails are divided, by means of insulated joints 2, into a plurality of successive track sections AB, BC, etc. Each such track section is provided with a track relay here designated by the reference character R with an exponent corresponding to the location and connected across the rails adjacent the entrance end of the sec-tion. Associated with each track relay R are two slow-acting relays designated by the reference characters K and J respectively, with exponents corresponding to the location. Each section is also provided with a trackway signal designated by the reference character S with a suitable exponent. Each signal S in the form here shown is located adjacent the entrance end of the section'which it governs and comprises .a semaphore arm capable of assuming three distinctive positions at 0, or 90 angular degrees with respect to the ground, thereby displaying a stop. a caution,'or a proceed indication. respectively. Associated with each signal S is a circuit controller designated by the reference character E with an appropriate exponent.

Each section is also provided with an oscillatory device or interrupter designated by the reference character D with an exponent corresponding to the location. Referring particularly to device D the device comprises two movable contact fingers 4 and 5 adapted to swing in unison on their pivots and to co-operate with fixed contact members 4 and 5*, respectively. These contact fingers are operated by an electromagnet 6 which is provided with a circuit which passes from a suitable source of energy such as a battery G, through wire 8, circuit controller E operated by signal S wire 9, magnet 6 of device D wire 10, contact 4-4 of device D /and

wires

11 and 12 back to battery G When signal S indicates caution or proceed the circuit" proceed although it is apparent that the circuit for magnet 6 may be governed by traflic in "the rear so as to conserve the energy of operation when not needed and to prevent unnecessary wear and tear on the contacts and bearings A pendulum 'or weight 7 is attached to the contact mechanism for the purpose'of stabilizing the device and defin ing the time period of oscillation. The time periodrequired for a complete cycle of device D that is, one stroke from right to left and one stroke from left to right, may be adjusted to any desired value and for purposes ofconvenience in explanation I will assume that each device D requires one second to complete a stroke and hence each complete cycle consumes two seconds.

Fixed contact 5 is arranged to co-operate with finger 5 in such manner that contact 5-5 is closed only when the finger is at the extreme left hand end of its stroke. When device D is oscillating then, this contact is closed for a brief interval of time once each cycle, that is, once each twofseconds. A device constructed as just described, may be made to oscillate with a very constant time period but it should be understood that any equivalent devices may be substituted for the devices D without departing from my invention.

Each track section is provided with a source of track circuit current such as a battery' designated by the reference cha a w H with a suitable exponent. Referring particularly to battery H one terminal of the bat- S is at stop and device D is'therefore at rest so that contact 5-5 is closed, section 13- 0 is supplied with continuous direct track circuit current, but when'signal S is at caution or proceed and device D therefore operating, section BC will be supplied with pulsating direct track circuit current, each impulse be: ing separated from the preceding impulse by a time interval of two seconds.

When track relay R is supplied with continuous direct track circuit current it is held in its energized condition and a circuit is closed for slow-acting relay K this circuit passing from battery G, through

wires

16 and 17 front contact 1818 of relay R wire 19, winding of relay K and

wires

20, 21, and 22, back to battery G Under these conditions relay K is held in its energized condition. If, however, relay R is supplied with pulsating direct track currentas hereinbefore explained, the relay is energized by each such impulse and is allowed to become de-energized during the interval between each two .consecutive impulses. During the brief period relay R is energized the circuit is closed for relay K which becomes energized. When next the track relay R becomes de-energized, the opening of'front contact 1818 thereon opens the circuit for relay K but this relay, due to its slow-acting characteristics, holds its front contact closed until its next succeeding energization. The closing of back contact 18-18 of relay R therefore closes a circuit for relay J B and current flows from battery G through

wires

16 and 17, back contact 18- 18 of relay R wire 23, front contact 2-124 of relay K wire 25, winding of relay J and

wires

26 and 22 back to battery G Relay J B is therefore energized, and, due to its slow-acting characteristics, thereafter holds its front contact closed as long as relay R is intermittently energized once each two seconds. When, however, relay R? is continuously closed, relay K is closed, but relay J B is open because its circuit is open at back contact 1818 of relay R 1 Each signal S is provided with an operating'mechanism havin a proceed circuit and a caution circuit. Re erring particularly to signal S when relays K and J are both energized, a proceed circuit is closed for this signal which passes from

battery G throughwires

16 and 27, front contact 2828 of relay K wires 29 and 30, front contact 3131 of relay J wire 32, operating mechanism of signal S and wire 22 back to battery G and the signal displays a proceed indication. When relay K is'energized and relay J B is de-energized, the caution circuit for signal S is closed and current flows from. battery G through

wires

16 and 27, front contact 2828 of relay K wires 29 and 30, operatingmechanism of'signal S and wire 22 back to battery G When this circuit is closed the signal indicates caution. When relays K and J are both de-energized, both circuits for signal S are open and the signal displays a stop indication. v

In explaining the operation of the apparatus as a whole I will assume that the section immediately to the right of point C is occupied by a train V and that the remaining portions of track shown in the drawing are unoccupied. Track relay R is therefore de-energized, and as a result slow-acting relays K and J C are both de-energized. Signal S therefore displays astop indication.

with track circuit current in the form of a series of direct current impulses each such impulse being separated from the preceding impulse by a time interval of two seconds. Relay R is intermittently ener gized at intervals of two seconds by the pulsating current thus supplied thereto and re-. lays K and J are both energized as explained hereinbefore. The proceed circuit for signal S is closed and the signal displays a proceed indication. The section to the left of point A is supplied with current in the same manner as section AB. Under certain conditions the distance between adjacent signals may be greater than v the maximum economical length for track sections. In such cases each section may be divided, as shown in Fig.2, by insulated joints 2,-into two or more sub-sections, such as B-W and WC. An auxiliary relay P Y is connected across the rails adjacent the entrance end of/sub-section W-C. When this relay is energized, an auxiliary track battery 33 is connected with the rails of sub-section B-W by means of-

wires

37 and 36 and front contact 35-35 of-relay P. A res1stance 34 is interposed between battery 33 and one rail 1 of section B--W for the same purpose as hereinbefore explained in connection with resistance 3. When relay P is degized to supply continuous direct track circuit current to sub-section B-VV, whereas when relay r is periodically energized at intervals of two seconds when device D is oscillating, relay R will be periodically energized by battery 33 at the same. intervals. It should be pointed out that a train occupying any part of section BC- will cause the de-energization of relay vR The operation of the apparatus will be understood without further explanation.

Referring now to Fig. 3, in the modified form of apparatus here shown the different indications are given by means of different codes, that is, by means of intermittent currents comprising groups of impulses separated by time intervals of different lengths.

As shown in the drawing alternating current of some convenient commercial frequency, such as 60 cycles per second, is used in place of the direct current of Figs. 1 and 2. Referring particularly to section BC device D associated with the section, in addition to the contact fingers already described, is provided with a third contact finger 38 arranged to move in unison with fingers 4 and 5 and adapted to engage

contact

38 or 38 at each end of each stroke.

Contacts

38 and 38* are connected together electrically and it there fore follows that when device D is oscillating the circuit including finger 38 is periodically closed for a brief interval at each end of each stroke. or twice each cycle,-that is, once each second.

Each device D is supplied with energy from an associated line transformer designated by the reference character Q with an exponent corresponding to the location. Referring again to device D the circuit for magnet 6 of this device passes from the secondary of transformer QP, through

wires

61 and 61. magnet 6 of device D wi-relO. contact 44* of device D and wires 99 and 67 back to transformer'Q This device therefore operates continuously.

lVhen signal S is at stop, a circuit is closed over which current flows from the secondary of transformer Q through wires 61*, 61 and 62, contact 3838 or 38-38 of device D wire 64, contact 4H5 of circuit controller E operated by signal S", Wires 65, primary 59 of track transformer T and

wires

66 and 67, back to transformer Q The secondary 58 of each track transformer T is constantly connected with the rails adjacent thee'xit end of the associated section and it is therefore plain that when signal S is at stop, section BC is supplied with energy in the form of successive groups of alternating current impulses, each group consisting of several alternations, the number of such alternations in any group depending upon the eriod during which contacts 3838 and 838 remain closed, and each group being separated from the preceding group by a time interval of one second. Energy supplied to the track under such conditions may 1 be termed caution code and is analogous to the caution code of Figs. 1 and 2.

The proceed code comprises groups of impulses each of which groups is separated from the preceding groupby a time interval of two seconds. This code is supplied to section BC when signal S is at proceed or caution, the circuit for transformer T then passing from the secondary of line transformer Q through wires 61 61, 62 and 63, contact 5 5 of device D wire 68, contact 4M3 of circuit controller E operated by signal S. wire 65, primary 59 of track transformer T and

wires

66 and 67 back to transformer Q Associated with eachtrack relay R is a time measuring device designated by the reference character U with a suitable exponent and comprising a motor device 73 together with a movable contact finger 74 operated thereby. Two fixed

contact members

75 and 76 co-operate with finger 74. The parts are so designed and proportioned -that when motor device 73 istde-energized, contacts 7475 and 74- 76 are open, and that following energization of motor device 7 3 one second elapses before contact 747 6 is closed and two seconds elapse before contact 7 1-7 5 is closed. Referring particularly to device U, a circuit is provided which passes from the secondary of transformer Q through

wires

71 and 17, back contact 1818 of track relay R wire 70, motor device 73 of time measuring- (leviceU and wires 77 and 72 back to transformer Q This circuit is closed only when relay B is de-energized. under which conditions motor device 73 is energized. Slow-acting relays K and J similar to those shown and described in connection with Fig. 1 are controlled by device U in the following manner: A circuit passes from the secondary of transformer Q through wires 71 and Y 17, front contact 18-18 of track relay R wire 78,- contact 7 47 6 of device U wire 7 9, winding of slowtransformer Q through wires 71 and'17,

front contact 1818 of track relay R wire transformer Q This circuit is closed only is therefore de-energized.

when relay B is energized and contact 74-75 of device U is closed under which conditions relay J U is energized. Each signal S is controlled by the associated slowacting relays K and J in the same manner as in Fig. 1.

I will now describe the operation of the apparatus as a whole: As shown in the drawing, the section immediately to the right of point C-is occupied by a train V. Relay R? The closing of back contact 18-18 of relay R energizes motor device 73 which closes both its contacts 74-75 and 74-7 6. The circuits for relays K and J C are both open at'front contact 18-18 of track relay R and these relays are de-energized so that signal S indicates stop. Contact 43-45 of-cireuit controller E is closed and current is being supplied to section B-C according to the caution code. Relay R is therefore periodically energized at intervals of one second. When relay B is de-energized, motor device 73 of device U 1s energized and slnce the duratlon of each de-energization of relay B is one second,

contact 747 6 is closed, but contact 74-7 5 is open. Each energization of relay R therefore momentarily closes the circuit for relay K before contact 7 47 6 opens, and relay K due to its slow-acting characteristics, holds its front contact closed between successive periods of energization. Relay J B is of course de-energized, and so signal S displays a caution indication. Contact 43-44 of circuit controller E is closed and proceed code current is being supplied to section A-B thus causing relay R to be energized for a brief interval once each two seconds. The periods of de-energization of relay R are sufficiently long to permit contact 74-75 of device U? to close and each energization of relay R therefore momentarily energizes both relays K and J before contacts 74-76 and 74-75 open. These slow-acting relays keep their front contacts closed between successive periods of energization and signal S therefore indicates proceed. If for any-reason. a device 1) sticks in the closed position, H or for any other reason steady current from any source is present in a track section, the

' track relay associated with this section will be constantly energized. Under this condition the associated motor-device U will per- 1nit both its contacts 74-75 and 7476 to open and the associated signal will display a stop indication.

Fig. 4 illustrates a modification of a portion of the apparatus shown in Fig. 3. In this modification single direct current 'im pulses are supplied to the track rails of each section instead of the groups of impulses of Fig. 3. Each device D is constantly opersuccessive impulses each'impulse being separated from'the preceding impulse by a time interval of one second. The source of track circuit current is a track battery H and under these conditions the circuit passes from battery H through rail 1 of section B-C, relay R rail 1 of section B-C, wire 15, resistance 3, wire 15*, contact 4445 of circuit controller E operated by signal S", wire 98, contact 38-38 or 38-38 of device D and

wires

40 and 13 back to battery H When signal S is at caution or proceed, section B-C is supplied with a proceed code consisting of a series of impulses each impulse by a'time interval of two seconds.

Under this latter condition the track circuit may be traced from track battery H through rail 1 of section B-C, relay R rail 1 of section B-C, wire 15, resistance 3, wire 15, contact 44-43 of circuit controller E operated by signal S", wire 41, contact 5-5 of device D and wire 13 back to battery H p Each of the track relays R, "of which only one, R is shown in the drawing, controls a time measuring device U and two slow-acting relays K and J which in turn control the associated signal in the same manner as already described in connection with Fig. 3. I

, The system shown in Fig. 1 issuitable for use with alternating current, the only changes necessary being the substitution of sources of alternating current for the batteries shown in this figure.

One feature of my invention is the elimination of line wires between signal locations, it being noticed that in the case'of direct current apparatus, no line wires are required, and in alternating current systemsembodying my invention, the only wires required between stations are the transmission wires 60 and 60.-

Another feature of my invention is that the signaling indications controlled by the time measuring means are rendered immune to foreign or unauthorized current which may enter the rails and affect the relay. These currents are fairly constant and do not assume the periodic character necessary to give a proceed indication. A constant energy condition may be used toflcause a restrictive indication such as the caution indication of Fig. 1 or the stop indication of Figs. 3 and 4, hence foreign current may cause one or the other of these indications but not a proceed indication. It is apparent therefore, that this invention may be applied to alternating current or direet current electrified railroads in-whichthe rails are utilized for the return path for the closed and one time period of open track section energy is utilized. Figures 3 and 4 illustrate my invention under circumstances in which two time periods are involved. It is apparent that only one of the energy conditions need be controlled and measured. For instance in Fig. 3 the time period of energ supply to the track may be the same regar less of the position of traflic controlled signal E providing the time periods of open circuit are difi'erent. Conversely the time period of open track circuit energy may be the same for all positions of signal E providing the time periods of energy supply are different.

Although I have. herein shown and described only a few forms and arrangements of railway signaling 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 invention. Having thus described my invention, what I claim is:

1. Railway signaling apparatus comprising a stretch of railway track, means for briefly supplying said stretch with energy at intervals the durations of which are dependent upon traflic conditions, and a trackway signal responsive to the lengths of said intervals'.

2. Railway signaling apparatus comprising a stretch of railway track, means for briefly supplying said stretch with energy at;

intervals, the durations of which are dependent upon traflic conditions, a trac'kway signal, and means responsive to the lengths of said intervals for controlling said signal.

3. Railway signaling apparatus comprising a stretch of railway track, means for briefly supplying said stretch with energy at intervals the duration ofwhich are dependent upon traflic conditions, a trackway signal, and time measuring means responsive to the lengths of said intervals for controlling said signal.

4. In combination, a stretch of railway track, a relay connected with the rails of said stretch, means for briefly sup-plying said rails with energy at intervals the durations of which are dependent upon trafiic conditions, time measuring means controlled by said relay and responsive to the lengths of said interval, and signaling means controlled by said time measuring means.

5. In combination, a stretch of railway track, means for supplying said stretch with pulsating energy each impulse being separated from the preceding impulse by atime interval the duration of which is dependent upon traffic conditions, and-a trackway signal responsive to the lengths of said intervals.

6. In combination, a stretch of railway track, means for supplying said stretch with pulsating energy each impulse being separated from the preceding impulse by a time interval the duration of which is dependent upon traflic conditions, time measuring means in the trackway responsive to the lengths of said intervals, and governing means controlled by said time measuring means.

7 In combination, a stretch of railway track, means for supplying said stretch with successive groups of impulses, each group being separated 'from'the preceding group by a time interval, time measuring means respon sive to the lengths of such intervals, and signaling means located in the trackway and controlled'by said time measuring means.

8. In combination, a stretch'of railway track, a signal for said stretch, means responsive to traflic conditions for supplying said stretch with pulsating current, each energy impulse being separated from the preceding energy impulse by a time interval during which energy conditions are substantially constant, and time measuring means responsive to the lengths of said intervals for controlling said signal.

9. In combination, a'stretch, of railway track, a signal for said stretch, a contact, means. operatingi under certain traflic conditions for perio i for a time interval, a source of energy, means including said contact for connecting said source with the rails of said stretch, and time measuring means responsive to the lengths of said intervals for controlling said signal.

10. In combination, a stretch of railway track, a signal for said stretch, a relay connected across the rails of said stretch, means operating when said stretch is unoccupied to energiie said relay at regular time intervals, and time measuring means controlled by said relay and responsive to the lengths of said intervals for controlling said signal.

11. In combination, a stretch of railway .track, a contact adapted at times to be periodically opened for uniform, time intervals, a source of energy, means including said contact for connecting said source with the rails of said stretch, a track relay connected with the rails of said stretch, a slow-acting relay controlled by said track relay, a second slow-acting relay controlled by said track relay and responsive tothe lengthsof said time intervals, and a trackway signal controlled by said slow-acting relays.

12. In combination, a stretch of railway track, a contact arranged to be periodically opened at times for uniform time intervals, a source of energy, means including said contact for connecting said source with the rails of said stretch, a track relay connected with the rails of said stretch, a slow-actingrelay adapted to be energized when said track recally opening said contact adapted to be energized when said track relay is de-energized and a trackway signal controlled by said first and said second slowacting relays.

13. In combination, a stretch of railway track, a motor device and a contact mechanism operated thereby, said contact being adapted to be periodically opened when'said motor device is energized, a source of energy, means including said contact for connecting said source with the rails of said stretch, a trackway signal for said stretch, a track relay connected with the rails of said stretch, and time measuring means controlled by said relay for controlling said signal.

14. In combination, a stretch of railway track, a signal for said stretch responsive to traflie conditions, a circuit controller operated by said signal, an oscillatory device controlled by said circuit controller-and having a substantially constant time period of oscillation and comprising a contact mechanism adapted to be closed for a brief interval once during each complete oscillation of the de vice, means including said conta t mechanism for-supplying energy to the rails of saidstretch, a track relay connected with the rails of said stretch, time measuring means controlled by said relay, and a second signal controlled by said time measuring means.

15. Railway signaling apparatus comprising means for supplying the tracliway with energy, time measuring means for at times periodically interruptin such supply for a time interval, and a trac way signal responsive to the lengths of said intervals.

16. Railway signaling apparatus comprising means for supplying the trackway with energy, time measuring means for at times periodically interrupting/such supply for a time interval, second time measuring means responsive to the lengths of such intervals,

. and a trackway signal controlled by said sec- 0nd time measuring means.

17 In combination, a stretch of railway track, means for supplying the stretch with energy in the form of successive impulses,

. each impulse being separated from the .pre-

ceding impulse by a time interval the duration of which is dependent upon traflic conditions, and a trackway si 'nal responsive to the lengths of said interva s.

18. -In combination, a stretch of railway track, a track relay for said stretch, means for periodically energizing said relay, each such energization bein separated from the preceding energization y a time interval the duration of which is dependent upon tralfic conditions, and a trackway signal for said stretch responsive to the lengths of such intervals.

19. In combination, a stretch of railway track, a device comprising a first contact closed once during a time period and a sec- 0nd contact closed twice during said time duration of which is dependent upon traffic 8 conditions, time measuring means controlled by said track relay, and a signal controlled by said time measuring means.

21. In combination, a stretch of railway track, a track relay for said stretch, means for periodically energizing said relay, each such energization being separated from the preceding energization by a time interval the duration of which is dependent upon traffic conditions, time measuring means controlled by said track relay, slow-acting means controlled by said time measuring means, and a signal controlled by said slow-acting means.

22-. In combination, a stretch of railway track, a track relay for said stretch, means for periodically energizing said relay, each such energization being) separated from the preceding energization y a time interval the duration of which is dependent upon traflic conditions, time measuring means controlled by said track relay, two slow-acting relays controlled by said time measuring means, and a signal controlled by said'slow-acting relays.

23. In combination, a stretch of railwag" track, a track relay for said stretch, mea for periodically energizing said relay, each such energization bein separated from the preceding energization by a time interval the duration of which is dependentupon traflic conditions, a motor device controlled by said relay, a contact controlled by said motor device and responsive to the lengths of said intervals, and a signal controlled by said contacts.

24. In combination, astretch of railway track, atrack relay for said stretch, means for periodicallyenergizing said relay, each such energization being separated from the preceding energization b a time interval the duration or which is ependent upon traffic, conditions, a motor device controlled by saidv relay, 0. contact controlled by said motor device and responsive to the lengths of said intervals, slow-acting means controlled b said contact, and a signal controlled by said slow-acting means. I

25. In combination, a stretch of railway track, a track relay for said stretch, means for periodically energizing said relay. each such energization being separated from the preceding energization by a time interval the duration of which is'dependent upon traflic conditions, a time measuring device controlled by said track relay and comprising a first contact adapted to be closed when such device is energized for a relatively short interval of time and a second contact adapted to be closed when such device is energized for a relatively long interval of time, and a signal controlled by said device.

26. In combination, a stretch of railway track, a track relay for said stretch, means for periodically energizing said relay, each such energization being separated from the preceding energization by a time interval the duration of which is dependent upon traffic conditions, a time measuring device controlled by said track relay and comprising a first contact adapted to be closed when such device is energized for a relatively short interval of time and a second contact adapted to be-closed when such device is energized for a relatively long interval of time, slow-acting means controlled by said device, and a signal controlled by said slow-acting means. I 4

27. In combination, a stretch of railway track, a track relay for said stretch, means for periodically energizing said relay, each such energization being separated from the preceding energization by a time interval the duration of which is dependent upon traffic conditions, a time measuring device controlled by said track relay and comprising a first contact adapted to be closed when such device is energized for a relatively short interval of time and a second contact adapted to be closed when such device is energized for a relatively long interval of time, a first slow-acting relay controlled by said first contact, a second slow-acting relay controlled by said second contact, and a signal controlled by said slow-acting relays.

28. In combination, a stretch of railway track, means for supplying said stretch with successive groups of impulses, each group being separated from the preceding group by a time interval, the duration of which is dependent upon traflic conditions, time measuring means locatediin the trackway and responsive to the lengths of such intervals, and a trackway signal controlled by said time measurmg mean 29. In combination, a stretch of railway track, means for supplying said stretch with successive groups of impulses, each group being separated from the preceding group by a time interval, time measuring means located in the trackway and responsive to the lengths of such intervals, slow-acting means controlled by said time measuring means, and a trackway signal controlled by said slow-acting means.

30. In combination, a stretch of railway track, means for supplying said stretch with successive groups of impulses, each group being separated from the preceding group by a time. interval, a track relay for said stretch, time measuring means controlled bysaid relay, and a signal controlled by said time measuring means.

31. In combination, a stretch of railway track, means for supplying said stretch with I for said stretch, time measuring means con trolled by said track relay, and a signal controlled by said time measuring means, in accordance with the lengths of such intervals.

32. In combination, a stretch of railway track, means for supplying said stretch with successive groups of impulses, each group being separated from the preceding group by a time interval the duration of which is dependent upon tratfic conditions, a track relay for said stretch, a time measuring device" controlled by said track relay and comprising a first contact adapted to be closed when such device is energized for a relatively short interval of time and a secondcontact adapted to be closed when such device is energized for a relatively long interval of time, and a signal controlled by said device in accordance with the lengths of such intervals.

33. In combination, a stretch of railway track, means for supplying said stretch with successive groups of impulses, each group be ing separated from the preceding group by a time interval the duration of which is dependent upon traflic conditions, a track relay for said stretch, a time measuring device controlled by said track relay and comprising a first contact adapted to be closed when such device is energized for a relatively short interval of time and a second contact adapted to be closed when such device is energized for a relatively long interval of time, afirst slowacting relay controlled by said first contact, a second slow-actingrelay controlled by said second contact, and a signal controlled by said slow-acting relay.

34. In combination, a stretch of railway track, a transformerhaving its secondary winding constantly connected with said stretch, means for supplying the primary winding of said transformer with successive groups of impulses, each such group being separated from the preceding group bya time from the preceding group by a time interval;

time measuring means responsive to the lengths of sald intervals, and a second trackway signal controlled by said time measuring means. I

37. In combination, a section of railway track, a signal responsive 'to traffic conditions in advance of said section, means controlled by said signal for supplying said section with energy in the form of successive groups of impulses, each such group. being separated from the preceding group by a time interval, the duration of which is dependent upon traf fie conditions, time measuring means for said section, and a second trackway signal controlled by said time measuring means in accordance with the lengths of such intervals.

38. In combination, a section of railway track, a signal responsive to trafiic conditions in advance of said section, means controlled by said signal for supplying said section with energy in the form of successive groups of impulses, each such group being separated from the preceding group of a time interval the duration of which is dependent upon traffic conditions, a track relay connected with said section, time measuring means controlled by said track relay, and a second trackway signal controlled by said time' measuring means and said relay.

39. In combination, a section of railway track, a signal responsive to traliic conditions in advance of said section, means controlled by said signal for supplying said section with trolled by said slow-acting relay.

40. In combination, a plurality of successive sections of railway track, a signal for each said .section, means controlled by each said signal for supplying the section next in rear with energy in the form of successive groups of impulses, each such group being separated from the preceding group bya tlme interval the duration of whichis dependent upon traffic conditions, a track relay for each groups of impulses supplied to the associated section.

41. In combination, a plurality of successive sections of railway track, train controlled means for each section, means controlled by such train controlled means for supplying the section next in rear with energy in the term of successive groups of impulses, each such group being separated from the preceding group by a time interval the duration of which is dependent upontraflic conditions, a track relay for each section, time measuring means controlled by each said track relay, slow-acting means for each section controlled by the associated track relay, and time measuring means for controlling the associated signal in accordance with the lengths of the intervals between groups of impulses supplied to the associated section.

42. Railway signaling apparatus compris ing a track section, a track relay for said section, a source of energy 'for said section, trafiic controlled means for alternately connecting said source to and disconnecting said source from said section, time measuring means controlled by said track relay for bridging the time period during which said source 1s connected with said section and the time period during which said source is disconnected from said section, and a track way signal controlled by said time measuringmeans. Y

43. ,Railway tratiic controlling apparatus comprising time measuring means in the trackway, meansfor causing constant and repeated operation of said time measuring means for different lengths of time according to traflic conditions, and trackway signaling means controlled by said time measuring means.

44:. In combination, a section of railway tracln'mean's for supplying the track rails of said sect-ion with coded signaling current the code characteristic varying in accordance with traliic conditions in advance of the section, a selector for said section responsive selectively to the different code characteristics of said current, and a trackway signal controlled by said selector.

45.111 combination, a section of railwa track, means for supplying the track rails of said section with coded signaling current the code characteristic varying in accordance with traffic conditions in advance of the section, a track relay connected with the rails trolled by said track relay and responsive selectively to the diiferent code characteristics of said current as repeated by the track relay, and a trackway signal controlled by said selector.

46. Railway traffic controlling. apparatus comprising a plurality of successive sections of railway track, a device for each section arranged when in operation to change in accordance with lapse of time, means for repeatedly and continuously operating each device for different intervals of time depending upon traffic conditions in advance of the associated section, and a trackway signal selectively controlled by each said device in accordance with the intervals of time during which such device is operated.

47. Railway traflic controlling apparatus comprising a stretch of railway track, means I for supplying said stretch with current in the form of code impulse combinations which vary in accordance with trallic conditions, and trackway signaling apparatus including a selector controlled in accordance with the code impulse combination of such current.

48. Railway traflic controlling apparatus comprising a stretch of railway track, means for supplying said stretch with current in the form of code impulse combinations which vary in accordance with traflic conditions, and trackway signaling means for giving different indicationsvdepending upon the code impulse combinations of such current but responsive to a steady condition of such current to display still another indication.

49. Railway traffic controlling apparatus comprising a trackway, means for supplying energy to said trackway in cycles each comprising a surge of energy and an interval of time during which the current value is zero, and a trackway signal controlled in accordance with the lengths of said intervals.

50. Railway trafiic controlling apparatus comprising a trackway, means forsupplying energy to said trackway in cycles each comprising a surge of energy and an interval of time during which the current value is zero, and trackway signaling apparatus including time measuring means selectively responsive to the lengths of said intervals.

51. Railway traflic controlling apparatus comprising a trackway,.trans1nitting means located in the trackway for supplying the trackway with code impulse combinations, and trackway signaling means including a selector continuously responsive to said code impulse combinations.

v 52. In combination, a section of railway track, a source of current for the rails of said section, coding means for periodically interrupting the supply of current from said source to said rails, a relay in the trackway controlled by the current in said rails from said source and having a release period greater than the period during which the supply of current from said source is interrupted when said coding means is in operation, and trackway signaling means controlled by said relay.

53. In combination, a section of railway track, a source of current for the rails of said section, coding means for periodically interrupting the supply of current from said source to said rails, a relay in the trackway controlled by the current in said railsfrom said source and designed to keep its armature closed after de-energization for a period greater than the period during which the supply of current from said source is interrupted when said coding means is in operation, and trackway signaling means controlled by said relay.

54. In combination, a section of railway track, a source of current for the rails of said section, coding means for periodically interrupting the supply of current from said source to said rails, a relay in the trackway receiving energy from said rails and arranged to release during each interruption of track current while said coding means is in operation, a second relay in the trackway controlled by the first relay and designed to keep its armature closed after de-energization for a period greater than that of each interruption of the track current while said coding means is in operation, and trackway signaling means controlled by said second relay.

ture.

HERBERT A. WALLACE.