US1879615A - Railway traffic controlling apparatus - Google Patents

Description

Sept. 27, 1932. A. E. HUDD RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Sept. 23. 1929 3 Sheets-Sheet 1 Hl'ffid EHudd Sept. 27, 1932. A. E. HUDD RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Sept. 25.1929 s Sheets-Sheet 2 i E 56 F 6 HZTF'd E. Hudd Sept. 27, 1932.

A. E. 'HupD RAILWAY TRAFFIC CONTROLLING APPARATUS :5 Shee ts-Sheet 5 Filed Sefit. 23, 1929 Patented Sept. 27, 1932 UNITED STATES PATENT OFFICE ALFRED E. HUDD, OF EVANSTON, ILLINOIS,ASSIGNOR, BY MESNE ASSIGNMENTS, To

ASSOCIATED ELECTRIC LABORATORIES,

TION OF DELAWARE INC., OF CHICAGO, ILLINOIS, A CORPORA RAILVJAY TRAFFIC CONTROLLING APPARATUS Application filed September 23, 1829 Serial No. 394,454.

The present invention relates in general to railway trafiic controlling apparatus, and particularly to signalling apparatus and'train control traclrway equipment for stretches of a single track over which trafiic moves in both the junction of the sections where the trackdirections.

The accompanying drawings, comprising Figs. 1 to l, inclusive, diagramatically illustrate sufficient circuits and apparatus to enable the invention to be readily understood.

Fig. 1 shows vehicle equipment of a train control system such asdisclosed in the copending Hudd application, Serial No. 377,418, filed July 11, 1929.

Figs. 2, 3, and l, when placed with Fig. 2 to the left of Fig. 3 and with Fig. 4: to the right of Fig. 3, show a stretch of track divided by means of insulated joints into a plurality of successive track sections, comprising a por- 2 tion or a section AB, sections BC, C-D,

l)E, EF, FG, G-H, H-I, IJ, and another incomplete section J K, respectively. Each track section is proviced with a track relay connected across the rails adjacent one end of the section and designated by the reference character T with a suitable exponent. A suitable source of current such as the track battery 7 extends across the other endof each section. A. resistor 8 is interposed between the battery 7 and one rail of the associated secand which is under the joint control of asso-- ciated track and pole-changing relays. At

way inductor magnets M are located are signals, designated S, with proper exponents. These signals are under the direct control of the line relays of the respective sections protected by such signals. At each signal location there is also provided a permanent mag net trackway inductor PM with a suitable exponent.

The trackway apparatus having been described in general the circuit details thereof will now be described. The circuit for line relay L for example, passes from a suitable source of energy such as battery 88, conductor 32, the upper contact and armature of relay 1 conductor 33, armature 34 and its contact, conductor 35, the contact and armature 36 of track relay T the winding of L conductor 38, common conductor 30, and the lower armature and front contact of relay P to the battery 88. This circuit is closed when relays P T and T .are energized. Under these conditions the relay L is energized in the normal direction and polarized armature 39 thereof is swung tothe left. If relay P is de-energized the circuit for relay L is the same as that traced except that current passes therethrough in the reverse direction and, consequently, the armature 39 is swung to the right. It will be obvious, therefore, that the relay L is energized in one direction or the other depending on the energized or de-energized condition of the pole-changing relay P The other line relays L to L inclusive, are each controlled over circuits similar to the one traced for the line relay L The track relays T to T, inclusive, are controlled in the usual manner i. e., Whenever the vehicle enters a section the track relay connected across the rails of such section drops its armatures.

The pole-changingrelay of each section is controlled by the track relay of the same section and by the track relay of an adjacent section. For example, the circuit for the pole-changing relay P extends from the pos itive terminal of battery Q}, conductor 26, the upper armature and contact of track relay T conductor 27, the upper contact and armature 28 and of track relay T the Winding of polechanging relay P conduc- .1

extends from battery supplied to the upper armature of the pole-changing relay P conductor 33, armature 34 and its contact, conductor 35, conductor 41, the contact and armature 42 of relay T conductor 43, armature 46 and back contact of track relay T the Winding of the inductor control relay 1 conductor 38, and common conductor 30, to battery 88 supplied to the lower armature of the pole-changing relay T When the circuit for I includes the front contacts of the arma-tures of pole-changing relay P the current flow is in the proper direction to cause the polarized armatures of relay I to swing to the left, whereas when the circuit is completed through the backcontacts of the pole-changing relay P the polarized armatures of relay I will be swung to the right. The remaining inductor control relays I to 1, corresponding to I are energized over circuits similar to the one traced for I When the inductor relay I is energized by way of the front contacts of the pole-changing relay it completes a circuit for the trackway inductor magnet M which extends, from the positive terminal of battery 83, through conductor 47, the armature 48 and contact of relay 1", the lower polarized armature and left contact of this relay, the conductor 50, conductor 51, through the upper and lower winding of trackway magnet M conductor 52, the left contact and upper polarized armature of relay I the front contact and armature 53 of this relay, and conductor 54 back to the negative terminal of the battery 83. The current flow in the magnet M in the direction traced, is appropriate to induce a magnetic field of north polarity in the upper and lower pole-pieces of magnet M and to produce a magnetic field of south polarity in the middle-pole piece of this magnet.

With the inductor relay I energized in the reverse direction a similar circuit is com pleted for trackway magnet M but since at this time the polarized armatures of I are moved to the right the current flow through M is reversed, and, consequently, under the latter condition the upper and lower polepieces of M will become of south polarity, while the middle pole-piece will be of north polarity. The remaining trackway electromagnet trackway inductors M to M M and M are controlled by their corresponding inductor control relays in the same manner as is M by the relay 1 While, to avoid complicating the drawings, the circuits of the inductor pairs, such asM and M are illustrated as including a single conductor 50. In practice it may be preferable to extend conductors 51 and 51' of these inductors individually direct to their controlling armatures on relay R and R respectively.

East-bound traffic over the stretch of track shown in Figs. 2, 3, and 4 is governed by trackway signals S S S S and S 10- relay L is energized in the normal direction,

current flows from battery 83, through the neutral armature and front contact of line relay L through the polarized armature 39 of this relay and its left contact and through the lamp G of signal S to the opposite terminal of the battery 83, thereby causing the signal S to display a proceed indication.

When the relay L is energized in the re Verse direction, current flowsv from the battery 83, through the neutral armature and front contact of relay L the polarized armature 39 of this relay and its ri ht contact, and through the lamp Y of signal S back to the battery 83, causing the signal S to display the caution indication.

If relay L is de-energized, current passes from the battery 83 through the neutral armature and its back contact and through the lamp R to the opposite terminal of the battery 83, causing the signal S to display a stop indication. The other wayside signals S to S, S and S are controlled in like manner by their associated line relays.

As shown in the drawings all. apparatus is in the position corresponding to that which it assumes under clear traffic conditions. Under these circumstances, all track relays are energized, all line relays are energized, and all pole-changing relays are energized, whereas all inductor control relays and all electromagnet trackway devices are de-energized. Since under these circumstances all pole-changing relays are energized, all line relays are energized in their proper direction to cause their associated signals to display a proceed indication.

The operations which occur as an east bound train proceeds along the track will now be explained. Prior to the entrance of a train into section AB, the pole-changing relay P becomes de-energized, thus causing relay L to be energized in the reverse direction, causing signal S to indicate caution.

As the train enters section B-C, track relay T is de-energized. The circuit for relay L is thereupon interrupted at armature 34. As a consequence, relay L becomes deenergized, causing lamp R of signal S to light and display a stop indication. The relay T, in dropping its middle armature, also interrupts the circuit of the pole-changing relay P which drops its armatures to reverse the direction of the current flow to the line relay of a section not shown, and at its uppermost armature interrupts the circuit of polechanging relay P thereby Causing the direction of current flow through the line relay L to be reversed. Consequently, the polarized armature of L swings to the right caus ing the signal S to change from proceed to caution. g

It will be observed that when the train enters section BC the west bound trafiic signal S will display a stop indication; the west bound traffic control signal S willdisplay a caution indication; while the west bound traffic control signal S will continue to display a proceed indication. As the description progresses it will be observed that these signals change progressively as the train passes through the various sections.

When the train enters section 0-1) the track relay T becomes deenergized, and at its armatures 28 and 56 opens asecond point in the circuit of pole-changing relays P and P, so that these relays will not become energizcd until the train clears section CD; at its armature 57 opens a second point in the circuit of the line relay (not shown) of secti on BC, which prevents the display'of the stop indication of signal S being changed to caution until the train is clear of sec tion CD at armature 36 opens a second point in the circuit of line relay L to prevent it from becoming energized until 7 the train clears section C-D; and at its armature 58 completes a circuit for the inductor control relay I similar to that traced for I The circuit for I extends from the positive terminal of battery 88, through the lower armature and front contact of pole-changing relay P common conductor 30, conductors 67 and 68, the winding of relay P, the back contact and armature 58 of track relay T conductor 69, armature 72 and contact of track relay T conductor 73, armature 74 and contact of track relay T conductor 75, and the upper armature and front contact of pole-changing relay P back to the negative terminal of battery 33. The polarized armatures of the inductor control relays are arranged to always remain in the position to which they are last moved. Therefore, the inductor controi relay 1 upon operating, simply lifts its neutral armatures, the current flow through its winding being at this time in the proper direction to maintain its polar armatures moved to the right. This relay at its lower and middle neutral armatures completes an energizing circuit for the trackway inductor magnet M similar to the one traced for M This circuit extends from the positive terminal of battery 83, conductor 47, the middle neutral armature and contact of inductor relay P, the lower polarized armature and right contact of this relay, conductors and 51, the upper and lower windings of M conductor 40, the upper right contact and armature of inductor relay I the middle contact and neutral armature of this relay, and conductor 54 to the negative terminal of the bat-' tery 83. As previously stated, when the current flow from the positive terminal of the battery passes through the upper winding of the trackway inductor first, the current flow is in the proper direction to produce an electromagnet of north polarity at each of the outer poles and of south polarity at the midpole of an energized electromagnet trackway inductor.

As will subsequently be made clear, the trackway magnet M is effective to neutralize or modifya condition set up in the train control equipment on the. vehicle by the permanent magnet PM When the train clears section BC the track relay T immediately becomes energized, but since the circuits shown controlled by it are now open at contacts of the track relay T the re-energization of T is without effect at this time.

hen the train enters the section D E track relay T becomes deenergized and interrupts the circuits of the pole-changing relays P 1?, and 'of' line relay L in the same manner as Were the corresponding relay circuits as a. result of the de energization of track relay T when the train entered section B-C. Accordingly, the pole-changing relay P becomes deenergized to prepare a circuit for operating the line relay (not shown) of section B-C in the proper direction to cause the signal S to display the caution in place of the stop indication when the train clears section C-D.

The relay T also, at its armature 111 interrupts the circuit of line relay L causing it to become deenergized and open the circuit of clear lamp G and complete the circuit of the stop lamp R of signal S The relay L upon becoming deenergized, at its neutral armature opens the circuit of caution lamp Y and completes the circuit for the stop lamp R of signal S.

The pole-changing relay P upon dropping its armatures reverses the direction of current flow through the line relay L in the same manner as such change was brought about in line relay L by pole-changing relay P when the train entered B-C.

When the line relay L moves its polarized armatures to the right, because of the circuit change brought about by the de-energization of pole-changing relay P, the displayed indication of signal S changes from proceed to caution.

When the train clears section C-D track relay T again becomes energized and, since the track relay T is now also energized, re-

establishes the circuits of pole-changing retion. The track relay T also at its armature 36 re-establishes the normal energizing circuit of line relay U, which functions to cause the proceed indication of signal S to be again displayed. Relay T at its armature 42, again closes a point in the operating circuit of inductor relay I and at its ar1na= duce any signal changes until after the train leaves section E-F in the same manner that the track relay T prevented the re-energization of track relay T from re-establishing circuits broken by it until after the train cleared section CD. The track relay T also at its armature 74 interrupts a. second point in the circuit of the line relay L which prevents the stop indication of the signal S from changing to caution until the train is clear of section E-F; at its armature 89 interrupts a second point in the circuit of line relay L, thereby causing the signal S to display its stop indication until the train clears section EF; and at its armature 91 completes a circuit for the inductor control relay I similar to that formerly traced for I to cause the tra'ckway inductor magnet M to become energized by current flow int-he same direction as that traced through the trackway inductor magnet M When the train enters section F-G the track relay T drops its armatures and causes changes to occur in its associated cireuitscorresponding to those which occurred when the train entered section DE; i. e. the track relay T when dropping its armatures interrupts the circuits of pole-changing relays P and P respectively, and interrupts the circuits of the line relays L and L The deenergization of these line relays L causes their associated signals S and S to display a stop indication; the de-energizatio-n of pole-changing relay 1? changes the direction of current flow toward the line relay L so that when the train clears section EF the latter line relay will become energized in its reverse direction and cause its associated signal S to display a caution indication. The relay P upon becoming deenergized, re verses the direction of current flow through the line relay (not shown) which controls the signal S causing that signal to display its caution indication.

hen the train clears the section EF circuit controlled by it is now opened at con tacts of track relay T The pole-changing relay P however, upon picking up its armatures restores the normal direction of current flow through the line. relay (not shown) controlling the signal S causing that signal to change from its caution to clear indication.

When the train enters section G-H, the changes which occur correspond to those which occurred when the train entered section E-F.

lVhen the train clears section F-G, the changes which occur correspond to those which occurred when the train cleared section DE.

WVhen the train enters section HI the track relay T drops its armatures to produce results corresponding those which were produced when the track relays T and T dropped their armatures.

When the train clears track section GH track relay T re-establishes circuits corresponding to those Ie-established when the track relay T picked up its armatures as the train cleared section EF.

When the train is in block HI, and clear of block GH, it will be observed that line relay L is de-energized, its circuit being open at armature 123; accordingly the associated signal S is displaying the stop indication; line relay'L is energized in the reversed di rection from normal because pole-changing relay P is deenergized, and consequently the associated signal S is displaying the caution indication; and line relay L which is energized in its normal direction, is causing signal S to display the proceed indication.

In order to explain how trackway inductor magnets M -to M have their conditions varied in accordance with traiiic conditions, it will be assumed that while a train is standing in the block section H-I a following train has entered section EF. lVhen the second train enters section E-F the track relay T influences the circuits and apparatus to the rear of the train in the same manner as did the train ahead of it. However, since the pole-changing relay P in the block occupied by the first train, is ale-energized at sequently, relay 1 lifts its neutral armatures and brings its polarized armatures to the left, thereby completing a circuit through its associated trackway magnet M in the reverse direction to that formerly traced.

It is to be noted at this time that the inductor control relay I at its upper neutral armature and contact completes a holding circuit for itself independent of the armature 98 of the track relay T so that as the train enters track section F-G and track.

relay T drops its armatures, the circuit of inductor control relay I will not be interrupted.

Referring now to Fig. 1, the vehicle equipment of an automatic train control system which will be properly influenced, in accordance with traflic conditions, by the trackway equipment shown; in Figs. 2 to 4, inclusive, will bedescribed. V

The equipment for receiving impulses transmitted from the trackway comprises a magnetic pick-up relay PR suspended from the locomotive tender in such a position that, as the tender passes over-the trackway, the relay will pass through the magnetic fields of inductor magnets PM to PM inclusive, and M to M inclusive. The receiver relay comprises armatures 107 to 107 which are adapted to be actuated by magnetism picked up from the trackway inductors by the magnetic flux collector plates associated with their pole-pieces 105 -105 respectively. The armatures 107 to 107 are held into association with eitherof their respective pole-piecesby magnetism of north polarity induced in their free ends by the small permanent magnets 103. Itmay be mentioned, however, that these magnets are very weak compared with those placed along the trackway, and therefore, the trackway magnets readily overcome the pull normally exerted on the armatures by the magnets 103. Associated with armatures 107 and 107 are a pair of armature restoring coils 108 which,

' when energized, are effective to move either or both of the armatures 107 or 107 into association with their pole-pieces105.

An electro-pneumatic valve EPV and an associated whistle W are provided to give ized.

the positive terminal of the vehicle battery.

a warning and initiate an automatic brake application upon de-energization of the electro-pneumatic valve in any desired manner, for example in the manner described in the co-pending application referred to.

Three lamp signals G, Y, and R under the joint control of the pick-up relay PR and of an auxiliary relay 110 serve to visually indicate the trafiic conditions proceed, caution, and stop, respectively.

The vehicle equipment is shown in the condition it assumes after passing a signal at clear. Under these circumstances the relay 110, electro-pneumatic valve EPV and proceed indicating lamp G are all ener- The circuit of EPV extends from VB, through the break contacts of push button PB, conductor 112, the contact and armatures 107 and 107 respectively, conductor 90, EPV, and conductor 97 to the negative terminal of the battery.

The circuit for relay 110 and lamp extends from positive battery on conductor 112, through contact and armature 107 conductor 113, armature107 and its lower contact to conductor 95 where the circuit divides, one branch extending through the lower Winding of relay 110 to conductor 97 and the negative terminal of the battery, while the other branch extends through proceed lamp G to the conductor 97 and the negative terminal of the battery.

In order to explain the operation of the vehicle equipment as influenced by the trackway equipment, it will now be assumed that a train is in the location of section H-I and that a second following train is in section C-D. The presence of a train in section CD causes the trackway magnet M to become energized, in the manner formerly described, to produce magnetism of north polarity at its outer pole-pieces and magnetism of south polarity at its middle pole-piece.

The trackway magnet M will be de-energized at this time owing to the de-energized condition of inductor control relay I and consequently, the trackway magnet inductor M has no influence on the vehicle equipment. As the receiver relay R passes over the permanent magnet trackway inductor'PM armatures 107 and 10? or armatures 107 and 107 are opertaed, depending on the polarity of the permanent magnet track element. The operation of either pair brings about the same circuit changes and it will, therefore, be assumed that the armatures 107 'and 107 8 are the ones operated; The armature 107 in operating, interrupts the traced circuit to the electro-pneumatic valve EPV, thereby causing the electro-pneumatic valve to become deenergized and initiate a brake application and at the same time to cause the whistle W to sound a warning to the engine men. The armature 107 interrupts the multiple circuit passing through the lower winding of relay 110 and proceed indicatinglamp G. Accordingly, the lamp G is extinguished, and the relay 110 de-energized. The stop indi cating lamp B does not light up, however, as its circuit is now open at'the armature 107 It should be stated that the trackway magnet M is located a sulficient distance in advance of PM to require less than a six-second period for the train to travel the distance between them when theivehicle is traveling at very. low speed. A distance of thirty feet between inductors has in fact been found to be quite satisfactory. When the trackway magnet M is encountered by the pick-up relay, since the outer pole-pieces of M are of north polarity, this magnet will be effective to restore armatures 107 and 107 because the trackway magnet M produces magnetism of north polarity in the pole-pieces 105 to 105 and induces magnetism of south polarity in the pole- pieces 105 and 105, respectively. Consequently, the armatures 107 and 107 are restored and the circuits for the proceed signal G, relay 110, and electro-pneumatic valve EPV are re-established, and no brake application occurs, as the equipment under the control of the EPV is arranged to delay the brake application for at least six seconds after its de-energization.

As the train proceeds and enters block EF, track relay T drops its armatures and thus completes the formerly traced circuit for inductor control relay 1 Since the polechanging relay P is de-energized at this time, owing to' the presence of a train in section HI, the current supplied to relay I in such a direction as to cause the trackway magnet M to energize to produce south polarity in its out pole-pieces and north polarity at its center pole-piece. When the tram passes over trackway magnet PM the vehicle equipment functions in the same manner as when passing over PM, but when passing over M this trackway inductor instead ofrestoring, armatures 107 and'1( )7 operates the armatures 107 2 and 107" owing to the magnetism of south polarity which it induces in the pole- pieces 105 and 105*. This action is further assisted by the magnetism of north polarity which it induces in pole- pieces 105 and 105. 7

Armature 107 in operating, merely breaks a second point in the traced circuit for the electro-pneumatic valve EPV, while the armature 107 in addition to breaking a second point in the traced circuit for the proceed indicating signal G and lower winding of relay 110, establishes a circuit for the cantion signal Y and upper winding of relay 110. This circuit extends from the positive terminal of the vehicle battery VB, the break contact springs of the push-button PB, conductor 112, the upper contact and armature 107, conductor 113, the armature 107 and its lower contact, conductor 114 and the upper winding of relay 110 and the caution signal Y in multiple to the negative terminal of the battery VB. Accordingly, the relay 110 is immediately energized to maintain the circuit of the stop signal R broken and the caution signal Y lights up to inform the engine-man that the wayside signal has been passed at caution and that acknowledgment must be made within the six seconds times allowed to avoid an automatic brake application occur- I1Il in engine-man, accordingly, momentarily operates the bush-button PB to energize armature restoring magnets 108 to re-establish W the circuit of the electro-pneumatic valve.

As the train enters section G-H the track relay T drops its armatures to close a point in the operating circuit of inductor control relay I, but since section H-I is occupied, T contacts 102 of the track relay T 1 are open; and, consequently, I will not be energized and, therefore, no current will flow in trackway inductor M". When the train receiver R passes over permanent magnet PM armature 107 will be operated as before to again initiate 'a brake application. The armature 107 will also be restored to its initial position, thereby interrupting the traced circuit through the upper winding of relay 110 and the caution signal Y. The engine-man now acknowledges as before, to re-establish the circuit of the electro-pneumatic valve, but since the armature 107 is now in engagement with the upper contact and relay 110 remains de-energized a circuit is completed for the stop signal R in the cab as follows:

From the positive terminal of vehicle battery VB, through the break contact of pushbutton PB, conductor 112, contact and armatume 107 contact and armature 107 conductor 96 the armature and contact of relay 110, through the lamp R to the negative terminal of the batery VB. It will be obvious, therefore, that a vehicle which proceeds into an occupied block section does so with the cab signal indicating stop.

The wayside signalling equipment and train control trackway equipment governing west bound traffic is identical to that used when traffic is east bound. It is, therefore, believed to be unnecessary to describe the operations which occur when a train passes over the track rails 1 and 2 in the opposite direction.

What is claimed is:

1. In combination with a single track railway equipped with an automatic block signalling system, a train control system having trackway equipment located midway between the rails thereof directly controlled by such signalling system, and vehicle equipment controlled by said trackway equipment to produce vehicle signals corresponding to the wayside signals of the signalling system encountered by the vehicle during its progress along the trackway, irrespective of the direction of movement of the vehicle.

2. In combination with a single track railroad, provided with wayside signalling equipment for each direction of traflic, train control equipment including trackway equip ment located centrally between the trackwayrails, means for controlling said equipment in a manner depending on the condition of said wayside signalling equipment, vehicle equipment responsive to influences transmitted to it by said trackway equipment as the vehicle passes thereover to faithfully reproduce, in the cab, the wayside signals displayed at the right side of the track, with respect to the direction of movement of the vehicle, irrespective of its direction of movement.

3. In a train control system, a trackway divided into blocks, an impulse transmitting equipment located between the rails at the point of division of two blocks, and vehicle carried signal means controlled by said equipment as the vehicle passes thereover to indicate in the vehicle any one of three possible tmflic conditions of the succeeding block irrespective of the direction of movement of the of the track relay vehicle.

l. In a train control system, a trackway divided into blocks impulse transmitting equipment located in a single line parallel to the track rails at the point of division of said blocks, vehicle carried signals for indi cating clear, caution and stop, respectively, and means actuated by said impulse transmitting equipment to cause the appropriate signal to be actuated irrespective of the direction of movement of the vehicle.

5. In a traflic controlling system a stretch or" track divided into insulated sections, a permanent magnet placed between the rails at the junction of two adjacent sections, an electromagnet placed to the rear of said permanent magnet and a second electromagnet placed in advance of said permanent magnet, a vehicle equipped with a train control relay, said permanent magnet comprising means for transmitting a magnetic impulse which operates said'relay as the vehicle passes thereover irrespective of the direction of movement, and tralfic controlled means for selectively energizing one or the other of said electromagnets to also operate said relay, the electromagnet selected depending directly upon the direction of movement of a vehicle.

6. In combination with a stretch of track divided into block sections; a set of wayside signals at the junction of two sections for displaying tralfic conditions in advance to a vehicle, equipped with cab signals, moving in either direction; a track magnet at said junction for transmitting an impulse to a passing vehicle to initiate an automatic brake application thereon and to extinguish any lighted cab signal, an electroinagnet track element on each side of said track magnet; and means for energizing one or the other or" said electromagnets, depending on the direction of movement of the vehicle, to cause one or another of said cab signals to be again lighted to reproduce on the vehicle the signal displayed along the wayside.

7. In an automatic block signalling system, a pair of relays at the junction of two adjacent blocks, a track relay for each of said blocks, energizing circuits for said first relays each including contacts of both of said track relays, and a stick circuit for each of said first relays excluding the contacts of one of said track relays.

8. In combination, a stretch of railway divided into block sections, a track relay at each end of each block, a circuit including a pole-changing relay and contacts of said track relays, a signal and signal control relay at the farther end of an adjacent block under exclusive control of certain of said track relays and said pole-changing relay, and a second signal and signal control relay at the end of the same block under control farthest from the signal of the adjacent block. a

9. In combination, a stretch of railway, divided into block sections, a track relay near the corresponding end of each section, a second track relay near the opposite end of each section, a set of pole-changing relays there being one for each section having an operating circuit" including contacts of the traclcrelays of such sections, another set oi: pole-changing relays there being one for each section also controlledby the track relays of such section, a signal control relay for one direction oftrafiic jointly controlled exclusively by the track relays and one polechanging relay of the first set and another signal control relay for the opposite direc- "tion of traffic jointly and exclusively controlledby the track relays and a ing relay of the other set.

10. In combination with a stretch of trackway over which trafiic moves in both directions, traclzway elements distributed along the traclzway midway between the rails thereof each in operative relation to vehicle carried apparatus directly actuated by each and every element individually irrespective of trafic conditions, the direction of movement of the vehicle, and of whether it is moving forward or backward, other elements distributed along the trackway in the same position relative to the rails thereof as are the first elements, and traffic controlled means for causing certain of said other elements to neutralize the effect produced on the vehicle by the first elements, partially neutralize such eiiect, or to fail to modify such effect depending on traffic conditions.

11. In a train control system, a group of train control trackway elements comprising a permanent magnet and a pair of electromagnets separted from each other a sufficient distance to insure against any appreciable interaction between their magnetic fields, vehicle equipment of a passing vehicle operated by the permanent magnet and also operable by said electromagnets when energized, and traiiic controlled means for energizing the last encountered electromagnet of the group providing the stretch of track immediately in advance of the vehicle is unoccupied.

12. In a train control system, a stretch of trackway divided into insulated block sections, a group of train control elements at the junction of two of said sections, said elements comprising a permanent and two electromagnets arranged with the permanent magnet between the electromagnets, a vehicle carried receiver operated by said permanent magnet each time the vehicle passes thereover, and means for energizing the subsequently encountered electromagne-t of the group to again operate said receiver in a manner depending upon traiiic conditions in advance.

pole-clung 13. In combination with a stretch of trackway divided into block sections, a group of train controlling trackway elements comprising a pair of electromagnets and a permanent magnet at the junction of each pair of adjacent block sections for controlling the movement of traffic in both directions in accordance with trafiic conditions, the permanent magnet of said group cooperating with one of its electromagnets to control the movement of traflic in one direction and with the other of its electromagnets to control the movement of traffic in the opposite direction.

In witness whereof, I hereunto subscribe my name this 18th day of September, A. D.

ALFRED E. HUDD.

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