US1959072A

US1959072A - Railway traffic controlling apparatus

Info

Publication number: US1959072A
Application number: US579243A
Authority: US
Inventors: Herbert A Wallace
Original assignee: Union Switch and Signal Inc
Current assignee: Hitachi Rail STS USA Inc
Priority date: 1931-12-05
Filing date: 1931-12-05
Publication date: 1934-05-15
Anticipated expiration: 1951-05-15

Description

May 15, 1934.

H. A. WALLACE RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Dec. 5, 1931 4 Sheets-Sheet l INVENTOR. HerberzAh izllace. QRW

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4 Sheets-Sheet 2 RN mm NE W N $8 0 n imm N Sm E mr w a 0% Y JJII%\ NNNN *9 m m 9%. K 1 M .L M M Mm T I Q INN mm: J x mt A w AL N [5 a P 1 S lm 9. N m

H. A. WALLACE RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Dec. 5, 1951 7 May 15, 1934.

May 15, 1934. H, A. WALLACE RAILWAY TRAFFIC CONTROLLING APPARATUS 4 Sheets-Sheet 3 Filed Dec. 5, 1931 m wm INVENTOR. He bemA Wallaee.

HIS A TTORNE Y.

y 5, 1934. H. A. WALLACE RAILWAY TRAFFIC CONTROLLING APPARATUS 4 Sheets-Sheeh 4 Filed Dec. 5, 1931 INVENTOR. 1 191 1901 64. 1462114100.

By QQW HIS A TTORNEY.

l atentecl May 15, 1934 UNITED STATES PATENT OFFICE RAILWAY TRAFFIC CONTROLLING APPARATUS Application December 5, 1931, Serial No. 579,243

31 Claims.

My invention relates to railway trafiic controlling apparatus, and particularly to apparatus for controlling switches and signals from a remote point such, for example, as the despatchers oifice in a centralized traflic controlling system.

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

The accompanying drawings, Figs. 1, 2, 3 and 4, when placed end to end in the order named, with Fig. l on the left, constitute a diagrammatic view showing one form of apparatus embodying my invention.

Referring to the drawings, the reference character X denotes the main track of a stretch of single track railway over which traffic may move in either direction. The two ends of a passing siding U are connected with track X by means of switches designated W and W respectively. A

' 2Q spur siding U is connected with track X by means of a switch W Spur siding U is also provided with a derail W One end of a second passing siding U is shown connected with track X by means of a switch W 5 Rails l and 1 of track X are divided by means of insulated joints 2 to form sections a-b, b-c, cd, d-g, g--h, h-z, i-Jc, 7 :-1n and m--n.

Rails

1 and 1 of siding U are similarly divided by insulated joints 2 to form a section e-f. Each of these sections of track X, and section e-f of siding U is provided with a track circuit which includes a battery 3 connected across the rails adjacent one end of the section, and a relay designated by the reference character T with a dis tinguishing exponent and connected across the rails adjacent the opposite end of the section.

A signal of the color light type, designated by the reference character S is shown for governing traflic movements from spur siding U to main track X. This signal comprises a stop lamp, designated by the reference character R, and two proceed lamps comprising a lamp Y for indicating caution and a lamp G for indicating clear.

All other signals shown in the accompanying drawings adjacent the points I), c, d, e, 1, etc., may be of the searchlight type, similar, for example, to the signal which is disclosed and claimed in Reissue Letters Patent of the United States, No. 14940, granted to Eli J. Blake on August 31, 1920.

' Each of these other signals is also capable of displaying a stop indication and two proceed indications, caution and clear, respectively.

Signals S S S and S govern eastbound trafiic movements on main track X. Signals S l S S and S govern westbound traffic movements on main track X. Signals S and S govern eastbound and westbound traflic movements, respectively, from track X to siding U Signals S and S govern eastbound and westbound trafiic movements, respectively, from siding U to track X. Signal S governs eastbound trafiic movements from track X to siding U and signal S governs westbound traffic movements from siding U to track X.

Each of the signals S and S is controlled automatically by the track circuits, is also controlled by the control apparatus for the next signal in advance, and is normally controlled for indicating caution except that the lamp for each of these signals is approach lighted and is therefore normally dark. Signal S is controlled automatically by track circuits in each direction, and is also controlled by the control apparatus for signals in each direction as well as by the positions of switch W and derail W All the other signals, each of which is designated by the reference character S with a numerical exponent, are controlled from a remote point such, for example, as the despatchers oihce of a centralized traffic controlling system. 0

Switch W and derail W may be operated between normal and reverse positions by any suitable manually movable means, not shown in the drawings. Each of the switches W W and W may be moved between normal and re- 5 verse positions by any suitable non-manual means such, for example, as a motor w comprising an armature 176 and a field winding 1'77, shown for switch W Motor w operates switch W through a link 1'72. This link is mechanically connected with a manually movable lever V which has a normal position p and a reverse position 1'. Lever V, upon being operated from its normal to its reverse position, moves link 172 out of connection with motor w and into connection with a second manually movable lever 21. Switch W may then be manually moved between its normal and reverse positions by means of lever o. Lever V is provided with a contact 9 which is closed if and only if lever V is in its normal position p.

The operation of motor w is controlled by mechanism designated by the reference character u. Mechanism u is controlled by approach locking relays designated by the reference characters M and M and is also controlled by relays C and C which may be controlled by codes originating in the despatchers oflice. Relay C controls mechanism u for operating switch W to its reverse position, and relay C '110 'then remain energized.

controls mechanism u for operating switch W to its normal position.

An approach locking relay, designated by the reference character M with a distinguishing exponent, is provided for each direction of trafiic movement for each of the switches W W and W All the pick-up and stick circuits for each approach locking relay M are controlled by a back locking relay, designated by the reference character L with an exponent corresponding to that of the associated relay M. Each relay L is so controlled as to be energized only when the home signal governing trafiic movements over the switch which is controlled by the associated relay M indicates stop, and only when the next signal in the rear of the home signal indicates caution or stop. One of the pickup circuits for each relay M is controlled by an approach relay which is designated by the reference character A with a corresponding exponent. Each relay A is controlled by track circuit conditions in the rear of the associated home signal. Certain of the relays A are also controlled by a signal in the rear of the associated home signal, and others of the relays A are controlled only by apparatus Which controls the next signal in the rear. Relay A for example, is controlled by relay P which is controlled by relay H and relay H is controlled by approach locking relay M which is, in turn, controlled by signal S similarly to the manner in which relay M is controlled by signal S through relay L as shown in the drawings. Relay A on the other hand, is controlled by relay C which controls signal S but relay A is not controlled by signal S Associated with the pair of approach locking relays'M for each switch is a time element relay Z which has a slow pickup characteristic. Each relay Z is controlled by either of two circuits each of which includes a front contact of a relay L, a back contact of the relay M with which the relay L is associated, and a front contact of the other relay M of the pair.

Each of the signals which is designated by the reference character S with a numerical exponent is controlled by a front contact of a relay designated by the reference character C with a corresponding exponent. Each of these relays C is a stick relay controlled from the despatchers ofilce, which if deenergized may be picked up in response to a distinctive code, so that its stick circuit will become closed and the relay will If a stick relay C is energized, it may be released by a different distinctive code, and will then remain deenergized. Each relay C controls one or more signal relays H, some of which are polarized. Certain of the relays H, in turn, control a slow release relay designated by the reference character P with a corresponding exponent. Each relay H and P directly controls a corresponding signal. Each of certain relays I-I, besides being controlled by a relay C, is controlled by a relay K which is, in turn, controlled by the switch over which an associated signal governs, and is controlled by track circuit conditions in advance of the signal as well as by back contacts of the C and P relays for an opposing signal, and by a front contact of the approach locking relay M which is associated with the same opposing signal. The polarity of the current supplied to each of the polarized relays H is controlled by pole-changing contacts of the relay P for the signal next in advance of the signal which is controlled by the relay H.

For controlling relay L signal S operates a contact 11 which is closed at all times except when signal S indicates clear; signal S operates a contact 12 which is closed at all times except when signal S indicates caution, and a contact 13 which is closed at all times except when signal S indicates clear; and signal S operates a contact 14 which is closed at all times except when signal S indicates caution, and a contact 15 which is closed at all times except when signal S indicates clear. Similar contacts designated by the same reference characters, respectively, are operated by signals S S and S for controlling relay L Each of the signals S and S which govern trafiic movements from opposite directions to siding U is controlled by a polarized relay D as well as by a neutral relay H. Each of these relays D is controlled by track circuit conditions between signals S and S The direction of energization of the relay D for each of these signals is controlled by an approach stick relay A associated with the other of these signals.

The control of signals S and S is such that either of these signals may be caused to indicate clear if there is no train in siding U and if there is no train on the approach section at the opposite end of siding U while the relay H for the signal at the opposite end of the siding is energized. If a train approaches either of these signals while the relay H for the signal is energized, the signal at the opposite end of the siding is compelled to indicate stop, and will continue to indicate stop after the train has entered siding U whereas the signal passed by the train is compelled to indicate stop only while the train occupies the track section in which the associated switch is located, after which the signal may indicate caution.

Contact 9 of the lever V for each of the switches W W and W together with a front contact of the track relay for the section in which the corresponding switch is located, controls a relay t which has an exponent corresponding to that of the track relay by which it is controlled. The home signals for governing traffic movements over the associated switch are controlled by the track relay for the section in which the switch is located, but are not controlled by the relay t for that section. The signals in each direction from these home signals for governing trafiic movements toward the home signals are, however, at times controlled by the relay 7? for the associated switch section. It follows that whenever a lever V is reversed to provide for manual movement of a switch W through its lever v, the home signals for governing trafiic movements over the switch may be controlled to display a proceed indication but the next signal in each direction from these home signals for governing traflic movements toward the switch will be caused to indicate stop.

Signals S and S are controlled by H and P relays similarly to the other main line signals which are designated by the reference character S with numerical exponents, but are not directly controlled by a front contact of a code relay C. Trafiic direction stick relays designated by the reference characters I and I for eastbound and westbound trafiic movements, respectively, are associated with signals S and S for selecting between following and opposing trafiic movements.

Control relay H for signal S is controlled by traffic conditions to the west of switch W that is, to the left, as shown in the drawings. Control relay H for signal S is controlled by trafiic conditions to the east of switch W that is, to the right, as shown in the drawings, and is also controlled by relay H Because of being controlled by relay H relay l-l is indirectly controlled by traffic conditions to the west of switch W Relay H can be energized only when a switch indication relay K is energized and when a switch indication relay K is deenergized. Relay K is energized only when switch W and derail W are both in their normal positions. Relay K is energized only when switch W and derail W are both in their reverse positions. It follows that relay H can be energized only when switch W and derail W are both reversed.

In each of the drawings, the contacts operated by the various relays are identified by numbers, such numbers having distinguishing exponents when the contacts are not shown adjacent the respective relays by which they are operated. The exponent for each of these contact numbers comprises the reference character and exponent for the respective relay. For example, the exponent T for contact 21 shown in one of the pickup circuits for relay M in Fig. 2 comprises the reference character T and its exponent 4 for track relay T which operates contact 21'. Similarly, exponent K for contact 22 in another circuit for the same relay M comprises the reference character K and its exponent 2 for switch indication relay K which operates contact 22 Having thus described, in general, the arrangement and location of the various parts of one form of apparatus embodying my invention, I will now explain the operation of the apparatus.

As shown in the drawings, all parts are in their normal condition, that is, each track section is unoccupied; derail W and each switch W are in the normal position; each lever V is in its normal position; each signal code relay C and each switch code relay G is deenergized; each 'normal switch code relay C is energized; each signal control relay H and each slow release relay P for signals having a reference character with a numerical exponent is deenergized; traffic direction relays I and I are deenergized; and each slow pickup relay Z is deenergized. With signal code relays C deenergized, the signals designated by the reference character S with numerical exponents, and which are controlled by the code relays C, are indicating stop. With switch W and derail W in the normal position, relay K is deenergized and, in turn, relays H and H are deenergized. Signal S is therefore controlled by relays H and H to indicate stop, but relay K is energized and hence the red lamp R of signal S which is controlled through a back contact of relay K is not lighted.

With the track sections unoccupied, each track relay T is energized. With each lever V in its normal position and with the corresponding track relay energized, each relay t is energized. Relay for example, is energized by a circuit which passes from terminal r of a source of current which is not shown in the drawings through contact 9 of lever V, contact 10 of relay T and the winding of relay i to terminal 0 of the same source of current.

With switch W in its normal position, switch indication relay K is energized by current of normal polarity supplied by the source having terminals as and 0, through a pair of pole-changing contacts 8 which are operated by switch W to the winding of relay K Relays K and K are similarly controlled by switches W and W With signals S S and S indicating stop, relay L is energized by a circuit which passes from terminal 11:, through contact 11 of signal S

contacts

12 and 13 of signal S",

contacts

14 and 15 of signal S and the winding of relay L to terminal 0. Relay L is energized by a circuit which is similarly controlled by contacts operated by signals S S and 8.

With the track sections unoccupied and the code controlled signals caused to indicate stop, each of the relays A for controlling a relay M is energized. A circuit for relay A for controlling relay M passes from terminal x, through back contact 16 front contact ll contact 19 of relay T and the winding of relay A to terminal 0. Relay A is energized by a circuit which passes from terminal 23, through the front point of contact 29 of relay P contact 30 of relay T contact 31 of relay T the winding of relay A and front point of contact 32 of relay P to terminal 0. Relay P which controls re lay A is itself controlled by a circuit which passes from terminal as, through the front point of contact 34 of relay H and the winding of relay P to terminal 0. Relay H is energized by a circuit which passes from terminal m, through contact 35 of relay M contact 36 of relay t contact 3'7 of relay H contact 38 of relay H contact 39 of relay C back point of contact 40 of relay P contact il of relay T front point of contact 42 of relay K contact 43 of relay T winding of relay H contact 44 of relay 1 front point of contact 45 of relay K and the back point of the contact 46 of relay P to terminal 0.

With relays L T and A energized, relay M is energized by a pickup circuit which passes from terminal at, through contact 20 of relay L contact 21', contact 23 of relay A and the winding of relay M to terminal 0. A second pickup circuit for relay M is also closed, and is the same as the first pickup circuit just traced except that it includes contact 22 closed in the left-hand position, instead of contact 21'. A stick circuit is also closed for relay M passing from terminal .1, through contact 20 of relay L front point of contact 24. of relay M and the winding of relay M to terminal 0.

Relay M is also energized by a pickup circuit which passes from terminal :13, through contact 52 of relay L contact53 of relay A and the winding of relay M to terminal 0. A stick circuit for relay M is also closed, passing from terminal r, through contact 52 of relay L front point of contact 54 of relay M and the winding of relay M to terminal 0.

Approach locking relay lvl associated with signal S is energized by pickup and stick circuits which are similar to those just traced for relay M Approach locking relay M associated with signal S is energized by pickup and stick circuits which are similar to the circuits traced for relay M With relays i M and M energized, and with code controlled relay 0 energized, mechanism u is energized by a circuit passing from terminal x, 7"

through contacts 178, 4 and 5 contact 7 of relay C and mechanism a to terminal o On account of mechanism 11. being energized by this circuit, switch W occupies its normal position. A similar circuit is also closed for energizing a mechanism a, not shown in the drawings, for each of the switches W and W Switches W and W are therefore also in their normal positions.

On account of track-relay T being energized, approach relay A which is shown adjacent the symbol for signal S is energized by a stick circuit passing from terminal as, through contact 60 of relay T contact 62 of relay A and the winding of relay A to terminal 0. A pickup circuit is also closed for relay A and follows the path just traced for the stick circuit for this relay except that it includes contact 61 of relay 1:) instead of contact 62 of relay A A second pickup circuit is also closed for relay A and differs from the first pickup circuit only by including a contact 1'79 instead of contact 60 of relay T A second stick circuit for relay A difiers in the same way from the first stick circuit.

Approach relay A which is shown adjacent the symbol for signal S is controlled similarly to relay A by pickup and stick circuits which include contact 60 of relay T and by a second pickup circuit and a second stick circuit which include a contact 179*.

With relay A energized, relay D which controls signal S is energized by current of normal polarity flowing from terminal 2:, through the front point of contact 63 of relay A contac 6 1 connected in multiple with contact 180 contact 65 of relay T contact 6S winding of relay D wire 67, and the front point of contact 68 of relay A to terminal 0. With relay A energized, relay D is also energized by current of normal polarity flowing from terminal 33, through the front point of contact 69 of relay A, contact 79 connected in multiple with contact 180 contact 71 of relay T contact 72*, winding of relay D wire 67, and front point of contact '73 or" relay A to terminal o.

With relays M andt energized, with track relays T and T energized, and with relay P deenergized, control relay ED for signal S is energized by current of reverse polarity which flows from terminal r, through contacts 13 i and 135 contact 136 of relay H contact 13'. of relay H contact 138 of relay C back point of contact 139 of relay P contact 140 of relay T contact 14-1 of relay T winding of relay H contact 1&2 of relay I and the back point of contact 143 of relay P to terminal 0. With relay E energized, slow release relay P is energized by a circuit passing from terminal ac, through the'front point of contact 144 of relay H and the winding of relay P to terminal 0. With relay H energized by current of reverse polarity and with relay P energized, the mechanism of signal S is held in a position for signal S to indicate caution, by a circuit passing from terminal as, through contact 145 of relay H closed in the right-hand position, the mechanism of signal S contact 146 of relay F, and contact 147 of relay H closed in the right-hand position to terminal 0. Although the mechanism of signal S is in the position for displaying the caution indication, lamp 175 for this signal is unlighted since its circuit is closed through back contact 148 of relay P only upon the approach or a westbound train.

uelay H for controlling signal S is energized by current of reverse "polarity supplied by a circuit already traced. With relay H energized, relay P is also energized by a circuit which includes the front point of contact 34 of relay H With relay H energized by current of reverse polarity and with relay P energized, the mechanism of signal S is energized by current of reverse polarity for causing this mechanism to occupy a position for signal S to display a caution indication. This circuit includes contacts 131 and 133 of relay H in the right-hand position, and also includes contact 132 of relay P Lamp 175 for signal S is, however, not lighted since it is controlled, through contact 130 of relay P by an approaching eastbound train.

Since switch W and derail W are in their normal positions, relay K is energized by a circuit passing from a suitable source of energy such, for example, as a battery 47, through a normally closed contact l8 of switch W normally closed contact 49 of derail W winding of relay K contact 50 of derail W and contact 51 of switch W back to battery 47.

With all parts of the apparatus thus in the normal condition, I will assume that the despatcher desires to permit an eastbound traific movement through the stretch of main track X in the eastbound direction, that is, from left to right as shown in the drawings. The despatcher therefore causes codes to be transmitted for energizing relays C and C Relay C upon becoming energized, opens its back contact 11"? in the circuit for relay H which is, however, already open at contact 120 of relay C Relay C upon becoming energized, also opens at its back contact 16 the circuit traced for relay A which, upon becoming deenergized, opens its contact 23 in the pickup circuits described for relay M Relay M however, continues energized by its stick circuit previously traced. With relay C energized, relay H for controlling signal S becomes energized in the reverse direction, by a circuit which passes from terminal ac, through contact 74 of relay P contacts '75 and '76, contact 78 of relay C back point of contact '79 of relay P contact 80 of relay T contact 81 of relay C winding of relay H and the back point of contact 82 of relay P to terminal 0. With relay H energized and with switch W in its normal position, relay P becomes energized by a circuit passing from terminal :2, through contact 83, contact 84 of relay K contact 85 of relay K closed in the left-hand position, contact 86 of relay H and the winding of relay P to terminal 0. Relay P upon becoming energized, opens its back contact 113 in the circuit for relay H which is, however, already open at contact 11? of relay C and at contact 120 of relay C as previously stated. With relay H energized in the reverse direction and with relay P energized, the mechanism of signal S becomes operated to the caution position by a cir cuit passing from terminal at, through contact 89 of relay H closed in the right-hand position, contact 88 of relay P mechanism of signal S and contact 87 of relay H closed in the righthand position to terminal 0.

Relay C upon becoming energized, opens, at its contact 138, the circuit previously traced for relay H which, thereupon becoming deenergized, causes relay P to become deenergized and open at its contact 146 the circuit previously traced for the mechanism of signal S The mechanism of signal S thereupon moves to the stop position. The deenergization of relay P causes its contact 130 to close and so causes lamp 175 of signal S to become lighted.

Upon the energization of relay C relay H for controlling signal S becomes energized by curtact 86 of relay H rent of normal polarity which flows from terminal {I}, through the front point of contact 29 of relay P contact 30 of relay T contact 31 of relay T contact 90 of relay C contact 91 contact 9.2 closed in the left-hand position, winding of relay H contact 93', and the front point of contact 32 of relay P to terminal 0. Relay H upon becoming energized, opens its contact 137 in the circuit for relay H which has already been deenergized by the opening of contact 138 of relay C With relay H energized, relay P becomes energized by a circuit which includes con- With relay H energized in the normal direction and with relay P energized, the mechanism of signal S becomes operated to the clear position by a circuit passing from terminal :1:, through contact 94 of relay H closed in the left-hand position, mechanism of signal S contact 95 of relay P and contact 96 of relay H closed in the left-hand position, to terminal 0-.

Upon the energization of relay P contacts '79 and 82 of relay P open at their back points and close at their front points, thus changing the polarity of the current supplied to relay H and causing the polar contacts 87 and 89 of relay H to be closed in the left-hand position. With contacts 87 and 89 closed in the left-hand position, the mechanism of signal S becomes operated to the clear position.

If the despatcher desires the train to continue on beyond point 'm, he will cause signal S to be operated to the caution or clear position by circuits which are similar to those already traced for signal S Upon the clearing of signal S contact 15 of signal S has become opened, thus causing relay L to become deenergized. The mechanism of signal S upon becoming operated to the clear position, opens its contact 11 also in the circuit traced for relay L The deenergization of relay L causes relay M to become deenergized on account of the opening of contact 20 of relay L in the stick circuit for relay M Relay M upon becoming deenergized, opens its contact 131 in the circuit for relay I-I which, however, is already open at contact 138 of relay C and at contact-137 of relay H as already pointed out. With relay M deenergized, contact 4 in the normal and reverse control circuits for mechanism 21, will open. It is clear that the position of switch W cannot be changed while either relay M or M each of which controls mechanism u for switch W is deenergized.

Relays M and M associated with signals S and S respectively, will become similarly deenergized when signals S and S are cleared. The deenergization of relays M and M will prevent any change in position of switches W and W Upon the deenergization of relay M its contact 114 opens in the circuit for relay H which is, however, already open at contact 113 of relay P at contact 117 of relay C and at contact 120 of relay C I will now assume that an eastbound train enters section ab. This causes relay T to become deenergized, and its contact will then open the first pickup and stick circuits for relay A which, however, continues energized by its second pickup and stick circuits which pass through contact 179 When the train enters section bc, relay T becomes deenergized, and relay t in turn, also becomes deenergized. The deenergization of relay T causes the circuit for relay P to become opened at contact 83. Relay P is therefore deenergized, permitting its contact 88 to open in the circuit for signal 5 the mechanism for which will therefore now move to the stop position. Upon the deenergization of relay P back contact 113 of this relay is again closed in the circuit for relay H On account of the deenergization of relay t when relay T becomes deenergized, relay t opens its contact 115 in the circuit for relay H The deenergization of relay T also causes its contact 1'7 to open in the circuit for relay A which is, however, already open at contact 16 as already pointed out. The deenergization of relay T also causes its contact '72 to open the circuit previously traced for relay D and causes its contact 64 to open the circuit traced for relay D As the train proceeds further and enters section cd, relay T becomes deenergized. With the mechanism of signal S in the stop position and with track relays T and T deenergized, relay M will then become energized by a pickup circuit which is similar to a pickup circuit which will later be traced for relay 1V1 through the back contacts 55 and 57. Relay M upon becoming energized, again closes its contact 114 in the circuit for relay H Relay T upon becoming deenergized, opens its contact in the circuit for relay H At the same time, contact 119 of relay T becomes opened in the circuit for relay H Contact 19 of relay T also opens in the circuit for relay A The train, upon entering section cZ-g, causes relay '1" to become deenergized which, in turn, causes relay i to become deenergized. At the same time, contact 93 opens the circuit previously traced for relay H thereby causing relay H to become deenergized and open: the circuit for relay P The deenergization of relay P causes its contact 95 to open the circuit for sig- 3 nal S the mechanism for which thereupon returns to the stop position. The deenergization of relay T also causes its contacts 66' and '70-" to open in the circuits for relays D and D respectively. Back contact 55', upon becoming closed, completes a second pickup circuit for relay M passing from the terminal as, through contact 52 of relay L contact 55, contact 56 closed in the left-hand position, contact 57, and the winding of relay M to terminal 0. Relay T upon becoming deenergized, closes its back contact 25 in a third pickup circuit for relay M which is, however, still open at contact 26. Upon the deenergization of relay i contact 135 is opened in the circuit previously traced for relay H and which is already open at contact 134 At the same time, contact '76 opens in the circuit previously traced for relay H and contact 178 opens in the circuit for control mechanism u for switch W The circuits for relay H and mechanism it therefore remain open as long as any portion of the train remains in section d-g.

' The train, upon entering section gh, causes relay T to become deenergized and open its contact 140 in the circuit for relay I-I Contact 60 of relay T also opens in the pickup and stick circuits previously traced for relay A Relay A however, continues energized by its second pickup and stick circuits which pass through contact 179 Contact 31 of relay T is also opened in the circuit for relays A and H On account of the mechanisms of signals S S and S all being now in the stop position, relay L is energized by its circuit previously traced. Upon the entrance of a train into section g-h, relay M therefore terminal 0.

becomes energized by its third pickup circuit, passing from terminal as, through contact 20 of relay L contacts 25 and 26', and the Winding of relay M to terminal 0. As soon as the rear end of the train leaves section dg, the despatcher can therefore again operate switch W if he so desires.

When the train enters section hi, relay T becoming deenergized, opens its contact 141 in the circuit for relay H and also opens its contact 30 in the circuit for relays A and H When the train enters section i7c, relay T becomes deenergized, causing its contact 152 to open in a circuit for relays H and H and also causing its contact 43 to open in the circuit for relay H The deenergization of relay I-I causes its contact 34 to open the circuit for relay P which, thereupon becoming deenergized, opens its contact 132 in the circuit for signal S The mechanism of signal S thereupon moves to the stop position. Relay P upon becoming deenergized, closes, through its contact 148, the lighting circuit for lamp 175 of signal Contact 29 of relay P also opens in the circuit for relays A and H The deenergization of relay T also causes a circuit to be cornpleted for a brief period of time for energizing relay I before slow releasing relay P opens its contact 126 at the front point. This circuit passes from terminal at, through contact 125 of relay T front point of contact 126 of relay P back point of contact 127 of relay P contact 128' of relay 1 and the winding of relay I to Relay I upon becoming energized, completes its own stick circuit which passes from terminal :11, through the back point of contact 34 of relay I-I front contact 129 of relay I and the winding of relay I to terminal 0. Relay I therefore continues energized by this stick circuit after relay P opens its front contact 126. Relay I will continue energized by this stick circuit as long as relay H remains deenergized.

When the train now leaves section h--i, relays H and A will become energized by current of reverse polarity flowing from terminal :13, through contact 33 of relay I back point of contact 32 of relay P and thence by the circuit previously traced, to the back point of contact 29 of relay P and the front point of contact 28 of relay I to terminal 0. With relay H thus energized in the reverse direction, contacts 94 and 96 of this relay will be operated to the righthand position, and hence current will be sup plied in the reverse direction to the mechanism for signal S causing this signal to now indicate caution.

I will next assume that all parts of the apparatus have been again returned to the normal condition, and that the operator then again causes code relays C and C to be energized'for.

clearing signals S and S I will also assume that the despatcher then causes relay 0 to again be deenergized before the arrival of a train, but that he permits relay C to continue energized. As already described, the clearing of signals S and S caused relay L to become deenergized and open the pickup and stick circuits for relay M With signal S returned to its stop indication as I have just assumed, signal S will have been returned to its caution indication on account of the deenergization of relay P which, through its contacts '79 and 82, has reversed the polarity of the current supplied to relay H for controlling signal S Relay L therefore again becomes energized by its circuit previously traced. The circuit for relay A however, remains open at contact 16 since relay 0 is still energized. The pickup circuits traced for relay M through contact 23 of relay A therefore remain open. The energization of relay L however, causes a circuit to be completed for energizing relay Z passing from terminal at, through contact 20 of relay L back point of contact 24 of relay M front point of contact 1'74 of relay M winding of relay Z and the back point of contact 173 of relay M to terminal 0. Relay Z having a slow pickup characteristic, closes its front contact 27 only after a measured interval of time has elapsed. The closing of this contact completes a fourth pickup circuit for relay M passing from terminal :c, through contact 20 of relay L contact 27, and the winding of relay M to terminal 0. The energization of relay M causes relay Z to be deenergized by the opening of its circuit at the back points of

contacts

24 and 173 of relay M Relay M then continues energized by its stick circuit previously traced.

I will now assume that the despatcher returns the apparatus to the normal condition, and then clears signals S and S by causing code controlled relays C and C respectively, to become energized. If signal S is controlled to indicate stop, the energization of relay C will cause relay H to become energized in the reverse direction, by a circuit passing from terminal at, through contact 113 of relay P contact 114 of relay M contact 115 of relay 1), contact 117 of relay. C back point of contact 118 of relay P contact 119 of relay T contact 120 of relay C winding of relay H and back point of contact 121 of relay P to terminal 0. Relay H upon becoming energized, completes a circuit for relay P passing from terminal r, through contact 105', contact 106 of relay K contact 107 of relay K in the left-hand position, contact 86 of relay H and the winding of relay P to terminal 0. With relay H energized in the reverse direction, and with relay P energized, the mechanism of signal S is operated to the caution position by a circuit passing from terminal :13, through contact 124 of relay H in the right-hand position, mechanism of signal S contact 123 of relay P and contact 122 of relay H in the right-hand position, to terminal 0.

The energization of relay P also causes relay I-I to become energized by current of normal polarity supplied through the front points of contacts 139 and 143 of relay P to the circuit previously traced. With relay H energized in the normal direction, the mechanism of signal S becomes operated to the clear position by a circuit passing from terminal at, through contact 145 of relay I-I in the left-hand position, contact 146 of relay P mechanism of signal S and contact 147 of relay H in the left-hand position to terminal 0.

The operation of the mechanism of signal S to the caution position causes its contact 14 in the circuit for relay L to open. The operation of the mechanism of signal S to the clear position causes its contact 11 in the circuit for relay L to open. Relay L being therefore deenergized, approach locking relay M is also deenergized due to the opening of contact 52 of relay L The energization of relay C causes a circuit to be completed for energizing relay H in the normal direction, by current passing from terminal at, through the front point of contact 151 of relay P contact 152 of relay T front point of contact 153 of relay K contact 154 of relay T contact 155 of relay C contact 156 of relay K contact 157 of relay K in the left-hand position, winding of relay H contact 158, front point of contact 159 of relay K and the front point of contact 160 of relay P to terminal 0.

The energization of relays C and H opens the circuit, previously traced for relay H at contacts 39 and 33, respectively. With relay H deenergized, contact 34 of relay H is open at front point in the circuit for relay P and hence relay P is deenergized, causing signal to indicate stop.

The circuits for signal S being similar to the circuits which I have described for signal S the clearing of signal S opens the circuit for relay L not shown in the drawings. The opening of the circuit for relay L causes relay M to become deenergized similarly to the manner in which relay L causes relay M to become deenergized.

I will next assume that the despatcher causes relay C to be again deenergized, but that he permits relay C to continue energized. The deenergization of relay C opens at its contact 120, the circuit for relay H which, in turn, opens the circuit for relay P causing signal S to indicate stop. With relay P deenergized, the current supplied to relay H will be of reverse polarity, causing signal S to indicate caution as previously described. With signal S indicating caution and signal S again indicating stop, the circuit previously traced for relay L is again completed, causing this relay to close its front contact 52. Relay A however, continues deenergized, since relay P is now deenergized and relay I has not become energized, and hence the circuit for relay A although being closed at the back points of contacts 29 and 32 of relay P is open at

contacts

28 and 33 of relay I Relay H is deenergized because its circuit is open at contacts 39 and 38 of relays C and H respectively, and also at contact 35 of relay M The energization of relay L therefore now causes a second circuit to be completed for energizing relay Z passing from terminal at, through contact 52 of relay L back point of contact 54 of relay M front point of contact 1'73 of relay M winding of relay Z and back point of contact 174 of relay M to terminal 0. Upon the lapse of a measured period of time, relay Z becomes energized and, through its contact 59 completes a third pickup circuit for relay M passing from terminal a, through contact 52 of relay L contact 59, and the winding of relay M to terminal 0.

I will assume that the despatcher now desires to permit a westbound train to enter siding U over switch W 2 reversed. He will therefore cause switch code relay C to become deenergized, and reverse switch code relay C to become energized. A circuit is thereby completed for energizing mechanism a for switch W passing from terminal a: through contacts 178*, 4 and 5 contact 6 of relay C and mechanism It to terminal o. Mechanism it, upon becoming thus energized, causes motor w to operate switch W to its reverse position. The operation of switch W to its reverse position reverses pole-changer 8, which is operated in conjunction with switch W thereby causing switch indication relay K to become energized by current of reverse polarity. Relay K therefore shifts its contact 107 from the left-hand position to the right-hand position.

The despatcher will now again cause signal code relay C to become energized. The energization of relay 0 completes a circuit for energizing relay H passing from terminal 0:, through contact 105, contact 106 of relay K contact 107 of relay K in the right-hand position, contact 108 of relay C and the winding of relay H to terminal 0. With relay H now energized, and with relay D energized in the normal direction as previously described, the mechnism of signal S is operated to the clear position by a circuit passing from terminal at, through contact 109 of relay D in the left-hand position, front point of contact 110 of relay D contact 111 of relay H mechanism of signal S, and the front point of contact 112 of relay ii) to terminal 0.

I will assume that a westbound train now enters section q-h, causing relay T to become deenergized and open its contact 60 in the first stick circuit and the first pickup circuit for relay A. The second pickup and stick circuits for relay A including contact 179 have already been opened on account of the energization of relay H Relay A therefore now becomes deenergized, causing current of reverse polarity to be supplied to relay D over the circuit previously traced for relay D except passing through the back points of contacts 69 and '73 of relay A instead of through the front points of these contacts.

Relay D upon becoming energized in the reverse direction, moves its contact 101 from the left-hand to the right-hand position, thereby opening an operating circuit for signal S which is similar to the circuit previously traced for signal S Even though the despatcher should by mistake cause relay H to be energized, signal S will not display a proceed indication while relay D is energized in the reverse direction.

Contact 101 of relay D in its reverse or righthand position, completes a third stick circuit for relay A passing from terminal 113, through contact 101 in the right-hand position, contact 62 of relay A and the winding of relay A to terminal 0 Contact 101 of relay D also now completes a third pickup circuit for relay A which is the same as the third stick circuit except that it includes contact 61 of relay D instead of contact 62 of relay A It is clear that as long as contact 101 of relay D remains in the right-hand position, relay A will continue energized by its third stick circuit even if relay '1 should become deenergized and open its contact 60 in the first pickup and stick circuits, and if relay H should become energized and open its contact 1'79 in the second stick and pickup circuits for relay A as well as if relay D should become deenergized and open its contact 61 in the third pickup circuit for relay A Each of the relays D and D is so designed and constructed that its contact 101 or 109, respectively, will remain closed in either direction until current of the opposite polarity is supplied to its winding. Contact 101 will therefore now remain closed in its right-hand position after the winding of relay D becomes deenergized.

If, now, the westbound train passes signal S relay T will become deenergized, causing its contact 105 to open the circuit for relay H Relay H upon becoming deenergized, opens its contact 111 in the circuit for signal S thereby causing signal S to indicate stop.

The deenergization of relay '1 also causes contacts 6S and TO of this relay to open the circuits for relays D and D respectively. The

deenergization of relay D opens, at contact 61 of relay D the three pickup circuits for relay A which, however, continues energized by its three stick circuits. Relay D upon becoming deenergized, permits its contact 61 to open. Relay A therefore, cannot become energized although contact 17E in the second pickup circuit for r ay A has closed when relay H became deenergized.

When the train proceeds into the siding and leaves section d-g, relay T will again become energized and complete the circuit previously traced for relay H Relay D is now deenergized because its circuit is open at contact 65 of relay T Contact 109 of relay D is, however, still closed in the left-hand position, and hence the mechanism of signal S is supplied with current of reverse polarity passing from terminal x, through contact 109 of relay D in the lefthand position, back point of contact 110 of relay D mechanism of signal S contact 111 of relay H and back point of contact 112 of relay D to terminal 0. A second Westbound train following the first train into siding U will therefore receive a caution indication at signal S after the first train has moved out of section dg.

I will next assume that, after the apparatus west of signal S has again been returned to the normal condition, a westbound train arrives in section gh, and that a trainman then reverses lever V preparatory to operating switch W by hand. The reversal of lever V causes link 172 to be connected between lever 22 and switch W The trainman thereupon moves switch W to its reverse position by means of lever c.

In order to now clear signal S the despatcher will again cause relay C to become energized,

which, in turn, causes relay H to become energized. Signal S will therefore be caused to indieate clear as before.

The movement of lever V to its reverse position opens, at its contact 9, the circuit for relay i thereby causing relay i to become deenergized and open its contact 135 in the circuit previously traced for relay H Relay H is, however, already deenergized. on account of contact 140 of relay T being open in the circuit for relay H Signal S is therefore indicating stop.

After the train has entered the siding and has moved out of section dg, the deenergization of relay i prevents the clearing of signal S although signal S will be caused to indicate caution.

I will now assume that the apparatus is again put into the normal condition, and that the despatcher desires to permit a train to move from siding U to main track X. Under these conditions, signals S 8, S and S are indicating stop, and signals S and S are indicating caution.

If, now, a trainman reverses derail W relay K will become deenergized due to the opening of contacts 49 and 59 which are operated by derail W With relay K denergized, a circuit is completed for red lamp R of signal S passing from terminal :c, through contact 165 of relay K back point of contact 166 of relay H in multiple with back contact 167 of relay H and lamp R to terminal 0.

Relay K upon becoming deenergized, permits its

contacts

42 and 45 to open at their front points which are included in the control circuit for relay H Relay H therefore becomes deenergized, causing relay P to, in turn, become deenergized. The deenergization of relay P causes contact 132 of this relay to open the operating circuit for signal S the mechanism of which thereupon moves to the stop position.

With relay P deenergized, lamp 175 of signal S is lighted by the circuit previously traced.

On account of relay P being deenergized, contacts 29 and 32 of this relay are now closed at their back points instead of at their front points. Relay I is also deenergized, and hence the reverse control circuit for relay H and the circuit for relay A are open at

contacts

28 and 33 of relay I causing relay A to be deenergized. The circuit for relay H is, however, also open at contact 90 of relay 0''.

On account of the deenergization of relay K contacts 153 and 159 of this relay are open at their front points which are included in the circuit for control relay H for signal S The circuit for relay H is, however, also open at contact 155 of relay C If the trainman now reverses switch W relay K will become energized by a circuit passing from battery 17, through contact 48* of switch W contact 49* of derail W winding of relay K contact 50 of derail W and contact 51 of switch W back to battery 4'7. The deenergization of relay K and the energization of relay K cause relay H to become energized in the normal direction by a circuit passing from terminal a, through the front point of contact 151 of relay P contact 152 of relay T back point of contact 153 of relay K winding of relay H contact 163 of relay K back point of contact 159 of relay K and the front point of contact 160 of relay P to terminal 0. Upon the energization of relay H relay H will become energized by current of reverse polarity flowing from terminal at, through contact 35 of relay M contact 36 of relay t contact 3'? of relay H contact 38 of relay H contact 39 of relay C back point of contact 40 of relay P contact 41 of relay T back point of contact 42 of relay K contact 164 of relay H winding of relay H back point of contact 45 of relay K and the back point of contact 46 of relay P to terminal 0. With relay H energized by current of reverse polarity, the yellow lamp Y of signal S will be lighted by a circuit passing from terminal a, through contact 165 of relay K front point of contact 166 of relay I-I contact 168 of relay H in the righthand position, and lamp Y to terminal 0.

I will next assume that a train movement is to be made from siding U to main track X while both signals S and S are displaying a proceed indication. Reversal of switch W and derail W will cause the deenergization of relay K and the energization of relay K as already described. Relay H will then become energized by current of normal polarity by the circuit previously traced. Relay H will now also become energized by current of normal polarity flowing through the front points of

contacts

40 and 46 of relay P in the circuit previously traced. With both relays H and H now energized by current of normal polarity, the green lamp G of signal s will be lighted by a circuit passing from terminal ac, through contact 165 of relay K front point of contact 166 of relay H contact 168 of relay H in the left-hand position, contact 170 of relay H and green lamp G to terminal 0.

I will now assume that the apparatus has again been returned to the normal condition, and that an eastbound train has then been permitted to pass signal S and occupies section cZ-g. The circuit for relay H" is therefore open at contact 135 and hence relay H is deenergized. With relay H deenergized, relay P is also deenergized because contact 1&4; of relay H is open at its front point. If, now, in preparation for moving a train from siding U to main track X, a trainman reverses derail W and switch W relay K will become deenergized and relay K will become energized as before.

Contacts

151 and 160 of relay P are now open at their front points which are included in the circuit for relay H previously traced. Since relay I is deenergized, contacts 161 and 162 of this relay are open, and hence relay H will not now become energized. Red lamp R of signal S will therefore become lighted, as previously described, by its circuit through the back point of contact 166 of relay H in multiple with back contact 167 of relay H I will now assume that a westbound train moving along track X enters section h-i at signal S Relay H is deenergized on account of relay 'I being deenergized, and hence relay P is also deenergized, and therefore when relay T becomes deenergized, a circuit is completed for energizing relay I passing from terminal :0, through contact 1&9 of relay T front point of contact 127 of relay P back point of contact j 126 of relay P contact 150 of relay I and the winding of relay I to terminal 0. On account of the deenergization of relay T relay H becomes deenergized. The stick circuit for relay D is therefore completed, passing from terminal :c, through the back point of contact 144 of relay H contact 171 of relay P, and the winding of relay D to terminal 0.

If, now. after the train has left section i-k, and while the train still occupies section hi,

-f' 1 a trainrnan, in preparation for a train movement from siding U to track X, reverses switch W and derail W relay K will become deenergized and relay K will become energized as previously described. Relay H will then become j energized in the reverse direction by a circuit passing from terminal at, through contact 161 of relay I back point of contact 160 of relay P and thence over the path previously traced for the circuit for relay I-I back to contact 151 of relay P thence through the back point of this contact, and through contact 162 of relay W to terminal 0. If signals S S and S are all controlled to indicate stop, relay H will now be energized by current of reverse polarity supplied by the circuit previously traced. Yellow lamp Y of signal S will therefore be lighted by its circuit previously traced.

I will next assume that the apparatus has been returned to the normal condition, and that the despatcher has then caused signal S to display a proceed indication. If, now, while signal S is displaying a proceed indication, and assuming that signal S is also displaying a proceed indication, the trainman reverses switch W and derail W preparatory to a train movement from siding U to track X, relay K will become deenergized, relay K will become energized, and relay H will become energized by current of normal polarity as previously described. Relay E will, however, now remain deenergized because relay C is energized and hence contact 39 of relay C is open in the circuit for relay H Red lamp R of signal S will therefore now be lighted by a circuit passing from terminal :0, through contact 165 of relay K back point of contact 166 of 'relay H and red lamp R to terminal 0.

I have described, for a few typical trafiic movements, the operation of one form of apparatus embodying my invention. From this description '80 and from the accompanying drawings, the operation of the apparatus for any other possible traflic movement will be readily understood.

From the foregoing description, it follows that apparatus embodying my invention provides the following features.

A. Approach looking for a switch in a centralised traffic control system, in which if a home signal for governing traffic movements over the switch is cleared, and if the next signal in the rear for overning traffic movements toward the home signal is cleared, and if the home signal is then put to stop but the next signal in the rear is left to indicate caution, or if the home signal is then put to stop while a train is appreaching the home signal, the approach looking will prevent operation of the switch for a given period of time. If, for example, both signals S and S are displaying a proceed indication, and if then signal S is caused to indicate stop while signal S continues to indicate caution, the first and second pickup circuits for relay M will remain open at contact 23 of relay A and hence relay M will not become energized. until relay Z has become energized.

B. Opposing signal control in a centralized traiiic control system, in which if a signal has been cleared and the next signal in the rear governing traffic towards the first signal has also been cleared, and if the first signal is then put us to stop but the second signal is left to indicate caution, or if the first signal is then put to stop while a train is approaching it, an opposing signal cannot be cleared for a given period of time. If, for example, both signals S and S are indicating clear, and if signal S is then caused to indicate stop while signal S continues to indicate caution, signals S and S cannot display a proceed indication until relay M has become energized after a measured period of time.

C. Opposing signal control, in which a circuit for a signal relay for controlling a signal includes a back contact of a code controlled relay for an opposing signal. For example, the circuit for 12.5 relay H for controlling signal S includes a back contact of relay C for controlling signal S D. Control of opposing signals for governing traffic movements into a siding, in which such a signal will indicate clear if the siding is un- 13g, occupied and the opposing signal is controlled to indicate stop; the signal will indicate caution for a second train which is following a first train into the siding; and the signal will indicate stop if the opposing signal is indicating caution or clear while a train is approaching it, or if the siding is occupied by a train which has entered the siding from the opposite direction. Signals S and S for example, are controlled in this manner.

E. Control of a signal for governing traffic movements from a siding over a switch which may be moved by manual means only, so arranged that the signal will indicate stop if a signal for governing trafiic movements toward the switch from either direction is displaying a proceed indication, or if a train between the switch and the nearest siding in either direction is approachng the switch; that the signal will indicate caution if the nearest receding signal in either direction is indicating stop and there is no approachingtrain between the switch and the nearest passing siding in either direction; and that the signal will indicate clear if the 5 approach signals in both directions are indicating stop while the receding signals in both directions are indicating either caution or clear and if there is no train'approaching. This refers to the control circuits for siding signal S F. Where a selector lever is used for transferring the operation of a switch from a motor to a manual lever, the home signals for governing trafiic movements directly over the switch are not controlled by the selector lever, but the approach signals next in the rear of the home signals are controlled by this lever.

Although I have herein shown and described only one form of railway traffic controlling 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 25 claim is:

1. In combination, a railway track switch, a signal for governing traffic movements from a given direction over said switch, a second signal for governing traffic movements from said given 1 direction toward said first signal but controlled independently of said first signal, and means controlled bysaid second signal for preventing an operation of saidswitch when said first signal indicates stop after said signals have contem- .iporaneously displayed proceed indications.

2. In combination, a railway track switch, a signalfor governing trafiic movements from a given direction over said switch, a second signal for governing trailic movements from said 1 given direction toward said first signal, signal control means, means controlled by said signal control means for controlling said second signal, a locking relay, a pickup and a stick circuit for said relay one of which is controlled by said first 1 signal and the other of which is controlled by said signal control means, and means controlled by said relay for controlling said switch.

3. In combination, a railway track switch, a signal for governing trafiic movements from a 1 given direction over said switch, a second signal for governing traffic movements from said given direction toward said first signal, a manually controlled device, means controlled by said device for controlling said second signal, a locking relay, a stick circuit for said relay controlled by said first signal, a pickup circuit for said relay controlled by said manually controlled device, and means controlled by said relay for controlling said switch.

4. In combination, a railway track switch, a

signal for governing traffic movements from a given direction over said switch, a second signal for governing traffic'movements from said given direction toward said first signal but controlled independently of said first signal, and means controlled by said second signal for preventing an operation of said switch for a measured period of time when said first signal indicates stop after said signals have contemporaneously dis- ;played proceed indications.

5. In combination, a railway track switch, a signal for governing tralfic movements from a given direction over said switch, a second signal for governing trafiic movements from said given "direction toward said first signal, a control in strument for controlling said second signal, and means controlled by said instrument for at times preventing an operation of said switch when said first signal indicates stop.

6. In combination, a railway track switch, a signal for governing traffic movements from a given direction over said switch, a second signal for governing traffic movements from said given direction toward said first signal, a control instrument for controlling said second signal, and means controlled by said instrument for at times preventing an operation of said switch when said second signal indicates caution while said first signal indicates stop.

7. In combination, a railway track switch, a signal for governing traific movements from a given direction over said switch, a second signal for governing traffic movements from said given direction toward said first signal, a control instrument for controlling said second signal, and means controlled by said instrument for preventing an operation of said switch for a measured period of time when said first signal indicates stop after having displayed a proceed indication.

8. In combination, a railway track switch, a signal for governing trafiic movements over said switch, a second signal for governing traflic movements over said switch, an approach locking relay controlled by said first signal and by a train approaching said first signal, a second approach locking'relay controlled by said second signal by a train approaching said second signal, a release relay, a circuit controlled by said first signal and by one of said approach locking relays for controlling said release relay, a second circuit controlled by said second signal and by the other of said approach locking relays for controlling said release relay, means controlled by said release relay for at times controlling said approach locking relays, and means controlled by said approach locking relays for controlling said switch.

9. In combination, a railway track switch, a signal for governing trafiic movements over said switch, a second signal for governing trafiic movements over said switch, a locking relay, a second locking relay, a release relay, means controlled by said signals and by said locking relays for controlling said release relay, means controlled by said first signal and by said release relay for controlling said first locking relay, means controlled by said second signal and by said release relay for controlling said second locking relay, and means controlled by said looking relays for controlling said switch.

10. In combination, a section of railway track, a signal for governing trafiic movements from a given direction into said section, a second signal for governing trafiic movements from said given direction toward said first signal, a third signal for governing trafiic movements from a second direction into said section, and means controlled by said second signal for preventing an operation of said third signal when said first signal indicates stop after having displayed 2. proceed indication.

11. In combination, a section of railway track, a signal for governing traffic movements from a given direction into said section, a second signal for governing traffic movements from said given direction toward said first signal, a third signal for governing trafiic movements from a second direction into said section, and means controlled by said second signal and by track circuit condi- Soi tions for preventing an operation of said third signal when said first signal indicates stop after having displayed a proceed indication.

12. In combination, a section of railway track, a signal for governing traffic movements from a given direction into said section, a second signal for governing traffic movements from said given direction toward said first signal, a third signal for governing traffic movements from a second direction into said section, and means controlled by said second signal for preventing an operation of said third signal for a given period of time when said first signal indicates stop after having displayed a proceed indication.

13. In combination, a section of railway track, a signal for governing trafiic movements from a given direction into said section, a second signal for governing trailic movements from said given direction toward said first signal, a third signal for governing traffic movements from a second direction into said section, a control device for controlling said second signal, and means controlled by said control device for at times preventing an operation of said third signal when said first signal indicates stop.

14. In combination, a railway trailic governing device, a section of railway track, a signal for governing traiiic movements from a given direction into said section, a second signal for-governing traffic movements from said given direction toward said first signal, a locking relay, means controlled by said second signal for preventing energization of said relay when said first signal indicates stop after having displayed a proceed indication, means controlled by a train upon passing said first signal for energizing said relay when said first signal indicates stop, and means controlled by said relay for controlling said traffic governing device.

15. In a centralized trafiic controlling system, a stretch of railway track, a signal for governing trafiic movements into said stretch from a given direction, a second signal for governing traffic movements from a second direction into said stretch, a code controlled stick relay at one end of said stretch, a first line circuit including a front contact of said relay for controlling said first signal, a second code controlled stick relay, at the other end of said stretch, and a second line circuit including a back contact of said first stick relay and a front contact of said second stick relay for controlling said second signal without controlling said second stick relay.

16. In combination, a railway passing siding, a signal for governing traffic movements into said siding from a given direction, a second signal for governing traffic movements into said siding from a second direction, and means controlled by a train upon entering said siding from either of said directions for causing the signal for the same direction to indicate caution and for causing the signal for the other direction to indicate stop.

1'7. In combination, a stretch of railway track, a signal for governing traflic movements into said stretch, a polarized relay having a normal polar contact and a front and a back neutral contact, means controlled by traffic conditions for normally energizing said relay by current of normal polarity for closing said front and polar contacts, means controlled by a train approaching said stretch for energizing said relay in the reverse direction for opening said polar contact, means controlled by a train occupying said stretch for deenergizing said relay, and means controlled by said relay for controlling said signal to indicate clear or caution according as said relay is energized or is denergized while said normal polar contact is closed.

18. In combination, a stretch of railway track, a signal for governing traffic movements into said stretch, a polarized relay having a normal polar contact and a front and a back neutral contact, means controlled by traffic conditions for normally energizing said relay by current or normal polarity for closing said front and polar contacts, means controlled by a train approach ing said stretch from a given direction for energizing said relay in the reverse direction for opening said polar contact, means controlled by a train entering said stretch from a second direction for deenerglzing said relay while said polar contact is closed, and means controlled by said neutral and polar contacts for controlling said signal to indicate clear or caution according as said relay is energized or is deenergized while said normal polar contact is closed.

19. In combination, a stretch of main railway track, a siding connected with said main track by a switch, a siding signal capable of indicating stop or caution or clear for governing traffic movements from said siding to said main track, approach signals for governing traffic movements from'opposite directions on said main track toward said switch, receding signals for governing trafiic movements in opposite directions on said main track away from said switch, a control device for each of said approach and receding signals, means controlled by the control devices for the approach signals for causing-said siding signal to indicate stop if one of said approach signals is controlled to display a proceed indication, and means controlled by the control devices for the receding signals for causing said siding signal to indicate caution" if one of said receding signals is controlled to indicate stop and for causing said siding signal to indicate clear if all said receding signals are controlled to display a proceed indication.

20. In combination, a stretch of main railway track, a siding connected with said main track by a switch, a siding signal for governing trafiic movements from said siding to said main track, approach signals for governing traffic movements from opposite directions on said main track toward said switch, a control device for each of said approach signals, and means controlled by the control devices for the approach signals for causing said siding signal to indicate stop if one of said approach signals is controlled to display a proceed indication.

21. In combination, a stretch of main railway track, a siding connected with said main track by a switch, a siding signal for governing traflic movements from said siding to said main track,

receding signals for governing traffic movements in opposite directions on said main track away from said switch, a control device for each of said receding signals, and means controlled by the control devices for the receding signals for causing said siding signal to indicate caution if any one of said receding signals is controlled to indicate stop.

22. In combination, a stretch of main railway track, a siding connected with said main track by a switch, a siding signal for governing trafiic movements from said siding to said main track, receding signals for governing traffic movements in opposite directions on said main track away from said switch, a control device for each of said receding signals, and means controlled by the control devices for the receding signals for causing said siding signal to indicate clear if all said receding signals are controlled to display a proceed indication.

23. In combination, a railway track switch, a motor for operating said switch, a manually movable lever, a selector lever for at times transferring the operation of said switch from said motor to said manually movable lever, a signal for governing traffic movements from a given direction over said switch, a second signal for governing traific movements from the same direction toward said first signal, means controlled by said selector lever for controlling said second signal, and means for operating said first signal independently of said selector lever.

24. In combination, a railway track switch, a signal for governing traffic movements over said switch, an instrument for controlling said signal, a second signal for governing trafiio movements over said switch, a second instrument for controlling said second signal, an approach locking relay controlled by said first instrument and by a train approaching said first signal, a second approach locking relay controlled by said second instrument and by a train approaching said second signal, a release relay, a circuit controlled by said first instrument and by one of said approach locking relays for controlling said release relay, a second circuit controlled by said second instrument and by the other of said approach locking relays for controlling said release relay, means controlled by said release relay for at times controlling said approach locking relays, and means controlled by said approach locking relays for controlling said switch.

25. In combination, a railway track switch, a signal for governing trafiic movements over said switch, a second signal for governing traffic movements over said switch, a first and a second instrument for controlling said first and second signals respectively, a locking relay, a second locking relay, a release relay, means controlled by said first and second instruments and by said locking relays for controlling said release relay, means controlled by said first instrument and by said release relay for controlling said first locking relay, means controlled by said second instrument and by said release relay for controlling said second locking relay, and means controlled by said locking relays for controlling said switch.

26. In combination, a stretch of railway including a detector track section, a switch leading from the detector track section, a signal to govern traffic through said detector track section, a route locking relay to control the operation of said switch arranged to permit operation of the switch when energized and to prevent operation of the switch when deenergized, means to deenergize said route locking relay when the signal is cleared, a normally deenergized slow-acting relay, a circuit effective to energize said slow-acting relay when a train occupies the detector track section arranged to pick up said slow-acting relay only after the energizing circuit has been closed a definite period of time, and a circuit means including a front contact of said slow-acting relay to at times energize said route locking relay.

2?. In a centralized trafiic control system for railroads, a stretch of single track, a control station at each end of said stretch, two opposing signals including one at each station for governing the movement of trafiic in said stretch, control means at each station governed from a central dispatchers ofiice for controlling the signal at such station, means eiiective when a signal is at stop to prevent the clearing of the opposing signal provided the stretch between said signals is occupied, approach locking means set into operation when a signal is put to stop if a train is approacl1in and is then within a predetermined distance of said signal, and effective when operated to prevent the clearing of the opposing signal even though the stretch between said signals is not occupied, and means for rendering said approach locking means ineffective upon the entrance of a train into said stretch.

28. In a centralized traffic control system for railroads, a stretch of single track, a control station at each end or" said stretch, two opposing signals including one at each station for governing the movement or" trafiic in said stretch, control means at each station governed from a central dispatchers ofiice for controlling the signal at such station, means effective when a signal is at stop to prevent the clearing of the opposing signal provided the stretch between said signals is occupied, approach locking means set into operation when a signal is put to stop if a train is approaching and is then within a predetermined distance of said signal, and effective when operated to prevent the clearing of the opposing signal even though the stretch between said signals is not occupied, and means for automatically rendering said approach locking means ineffective at the end of a measured time interval.

29. In a centralized traflic control system for railroads, a stretch of single track, a control station at each end of said stretch, two opposing signals including one at each station for governing the movement of traifio in said stretch, control means at each station governed from a central dispatchers cifice for controlling the signal at such station, means effective when one of said signals has been cleared to prevent the clearing of the opposing signal, approach locking means set into operation when one of said signals is put to stop by said control means if a train is ap proaching said signal and is then within a predetermined distance or" said signal, and effective when operated to prevent the clearing of the opposing signal, and means for automatically rendering said approach locking means ineffective at the end of a measured time interval.

30. In a centralized traffic control system for railroads, a stretch of single track, a control station at each end of said stretch, two opposing sig-- nals including one at each station for governing the movement of traffic in said stretch, control means at each station governed from a central dispatchers ofiice for controlling the signal at such station, means effective when one of said control means is operated for clearing a signal while the stretch is unoccupied and the opposing signal is at clear to put said opposing signal to stop, approach locking means set into operation when said opposing signal is put to stop by said control means if a train is approaching said signal and is then within a predetermined distance of said signal, and effective when operated to prevent the clearing of the first named signal, and means for automatically rendering said approach locking means ineffective at the end of a measured time interval.

31. In a centralized traffic control system for railroads, a control station including a track switch at each end of said stretch, two opposing signals including one at each station for governing the movement of trafiic in said stretch, consaid relay for controlling the switch at the same station and. the signal at the other station, means for picking up each said relay when a train enters said stretch, and time controlled means for picking up each said relay when the stretch is not occupied and the signal at the same station is at stop.

HERBERT A. WALLACE.

DISCLAIMER 1,959,072.Herbert A. Wallace, Edgewood', Pa. RAILWAY TRAFFIC CONTROLLING APPARATUS. Patent dated May 15, 1934. Disclaimer filed July 17, 1936, by the assignee, The Union Switch dc Signal Company. Hereby disclaims the subject matter of

claims

5, 6, 7, and 13.

[Ofilclal Gazette August 18, 1986.]