US2117691A - Railway traffic controlling apparatus - Google Patents

Description

May 17, 1938.

E. M. ALLEN ET AL RAILWAY TRAFFIC CONTROLLING APPARATUS Original Filed Dec. 29, 1930 2 Sheets-Sheet l R2 TR INVENTOR-S' ,M, filler? .14, liroakq Pr. Th ornpson, 02% W (J MATTORNEY.

May 17, 1938. E. M. ALLEN ET AL RAILWAY TRAFFIC CONTROLLING APPARTUS Original Filed Dec. 29, 1930 2 Sheets-Sheet 2 ATTORNEY.

Patented May 17, 1938 UNITED STATES PATENT OFFICE RAILWAY TRAFFIC CONTROLLING APPARATUS Vania.

ApplicationDecember 29, 1930, Serial No. 505,328 Renewed March 6, 1933 45 Claims.

Our invention relates to railway trafiic controlling apparatus for governing trafiic over a stretch of railway wherein there is located a switch, and more particularly it relates to appa' ratus suitable for use in an interlocking system whereby the movements of the switch and the signals associated therewith are controlled from a remote point such, for example, as a central office. In systems where the movements of a railway switch and its associated signals are controlled from a remote point, it is customary to provide approach locking circuits. An object of our invention is to insure that the approach locking has functioned before a signal governing a movement over the switch can be cleared, thereby making it impossible to clear the signal governing trafiic over the switch in question, unless it has become fully locked previous to the clearing of the signal. In centralized traffic controlling systems, it is desirable to permit a route to be set up and a signal cleared, and to permit theselection of a reverse control circuit for the switch which will function to reverse the switch immediately after a train has accepted the signal of the first route and vacated the detector track circuit. This requirement makes it very necessary to provide a continuous check on the approach looking to insure that the switch does not prematurely operate. Another object of our invention is to provide a continuous check on the approach looking and thereby prevent the loss of approach look-- ing from occurring and reduce to a minimum the possibility of the false operation of a switch while a train is approaching.

The apparatus of our invention is an improvement over that disclosed in the copending applications, Serial No. 125,659, filed July 29, 1926, by H. A. Wallace, for Railway traffic controlling apparatus; Serial No. 279,062, filed May 19, 1928, now Patent No. 2,057,543, granted Oct. 13, 1936, by L. E. Spray, for Remote controlling apparatus; Serial No. 313,772, filed Oct. 20, 1928, by H. A. Thompson, for Multiple control apparatus; Serial No. 334,081, filed Jan. 21, 1929, now Patent No. 2,053,928, granted Sept. 8, 1936, by H. C. Vantassel, for Remote control apparatus; Serial No. 379,- 163, filed July 18, 1929, by C. A. Brooks, for Multiple control apparatus; and Serial No. 416,- 061, filed Dec. 23, 1929, by H. A. Thompson, for Multiple control apparatus.

Again in centralized traific control systems it is often desirable that a single operation or code will initiate a movement of the switch and clear the signals permitting traffic over the new position of the switch. This requirement makes it essential to insure that the two operations, that of moving the switch and that of clearing the signals, will follow in the proper sequence. Another object of our invention is to provide that agreemerit betweenthe switch repeater relay and the switch control relay must be obtained before the signal control relay can be energized thus insuringproper sequence of operation. Again, in

order that a code for a reverse movement of the switch may be stored after the switch has been set and a signal cleared, provision is made in our invention that the signal once cleared will remain in that position until accepted by a train even though a disagreement between the signal control relay and the switch repeater relay has been later brought about by the storing of a reverse movement of the switch. In respect to thesefeatures, our apparatus is an improvement over that disclosed in the copending applications, Serial No. 373,675, filed June 25, 1929, by L. V. Lewis, for Remote controlling apparatus, and Serial No. 538,380, filed May 18, 1931, by C. S. Snavely, A. B. Miller, and R. H. Tunell, for Remote control systems. vention will appear as the specification progresses.

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

Figs. 1 and 2, when placed end to end with Fig. 1 on the left, form a diagrammatic View of one form of apparatus embodying our invention when applied to a stretch of railway including a single switch and its associated signals.

Referring to the drawings, a railway switch designated by the reference character SW is operated by any standard type of switch machine shown in the Fig. 1 by a symbal which is designated by the reference character SM. The operating circuits for the switch machine SM are not shown in the figures as they form no part of our invention, and they may be of any one of the several types well known to the art. In this instance, the control of the switch machine SM is by means of coderelays to be referred to later. It will be understood, however, that our invention Other features of our inis not limited to this one system of control, but that other methods may be employed. For example, the control may be by means of controllers operated by levers of a tower machine, or by relays controlled automatically.

By means of insulated rail joints 3, the track rails l and 2 of the stretch of railway are divided into track sections L3T, L2T, IT, RZT and RST. The track sections L3T, L2T, R2T and R3T will be referred to as approach sections, while the section IT will be referred to as a detector track section. Each track section is provided with a customary track circuit which includes a track battery and a track relay connected to the rails in the usual manner as will be readily understood from the Figs. 1 and 2. The wayside signals for governing traffic over the switch SW from the right to the left, in the Figs. 1 and 2, are designated by the reference characters L2 and L3, and the signals governing trafiic from the left to the right are designated by the reference characters R2, R3 and RM. These signals may be of any of the well known types but, as here shown, are color light signals. of the Searchlight type, such as disclosed in United States Letters Patent Reissue No. 14,940, granted to E. J. Blake. The signal L2 is provided with three mechanisms indicated by the reference characters a, b and 0. Each mecha nism consists of a motor operated relay which includes two windings d and 5. The winding 4 of mechanism a for the main signal is constantly supplied with power from a convenient source, not shown in the figure, but whose positive terminal is designated by the reference character B and whose negative terminal is designated by the reference character C. With the winding 5 of mechanism a energized in a manner to be later described, it displays a proceed signal. When either winding 4 or 5 is deprived of power, the mechanism (1 assumes its most restrictive condition and displays a stop signal. The mechanism a operates movable controller contacts S and l in such manner that when it is set to display a stop signal, both controller contacts 6 and l are in engagement with the fixed lower contacts 8 and 9, respectively, while with the mechanism a set to display a proceed signal, then controller contact I breaks engagement with fixed contact 9 and is shifted to make engagement with the upper fixed contact ID. The mechanisms 22 and c of the signal L2 are similar in construction to the mechanism a and operate a similar pair of controller contacts. The mechanism b of signal L2, as is the usual custom, governs traific to the siding when the switch SW is reversed. The mechanism is a call-on signal. The a and c mechanisms of the signal R2 are similar to the mechanisms at and c of the signal L2, respectively, while I) of R2 is a fixed signal displaying stop only. The signal R2d is a dwarf signal governing traffic moving from the siding to the main line and having a mechanism d similar to mechanism 0 of R2. The mechanism a of the signal L3 is similar to mechanism a. of L2 already described, except that it is arranged to operate in three positions. With its winding 4 continuously energized with a given polarity of current then when its winding is energized with one polarity of current it is set to display a caution signal, and when winding 5 is energized with current of the reverse polarity, it is set to display 2. proceed signal. With mechanism a of signal L3 set to display a proceed signal, its controller contact I is shifted to engage the top contact l0, and controller contact 6 is left in engagement with the lower contact 8. When it is set to display a caution signal, the contact 6 is lifted to engage contact H, and l is in engagement with 9. The signal R3 is similar to the signal L3 and needs no further description. As stated above, our invention is adapted to the use of any standard type of signals inasmuch as the operating circuits of the signals form no part of our invention, and the relay mechanisms here shown may be relays operating armatures that control circuits for motor operated signals, or the circuits of other types of light signals.

In order to simplify the figures somewhat and to make the circuits easier to understand, We have, in a number of instances, especially in the signal control network, placed a circuit controlling armature in a location in the figure that is not adjacent to the relay that controls the armature. In all such instances the armature is designated by a reference character with an exponent corresponding to the reference character of the controlling relay, and all such armatures are shown in the position corresponding to the normal position of the relay. For illustration, the circuit controlling armature designated by the reference character ZQ in Fig. 1, is operated by the track relay TR of Fig. 2, and the armature 20 normally occupies its raised position, inasmuch as the relay TR is normally energized.

The code relays GY, 6X, 'lY, IX and CS are shown in Fig. 2 as located on a panel indicated by dotted lines. In the specific form of our invention herein illustrated, it is to be understood that these code relays are to be controlled in the manner illustrated in Fig. 13 of the Snavely, Miller and Tunell application hereinbefore referred to, but since the control circuits for these code relays form no part of our invention they are omitted from the figures for the sake of clearness. For a description of our invention it is deemed sufficient to say that these relays 6Y, 6X, 'lY, IX and CS are selectively energized or deenergized from some central point such as a despatcher office, and when energized, these relays lift their armatures to engage front contacts and when the relays are deenergized, their armatures drop into engagement with back contacts.

The circuit controllers l2, l3 and M of Fig. 1 are operated by the switch SW as indicated by a dotted line. Each controller occupies an upper position in the figure as shown by the solid line when the switch is set for the main line, while each controller is shifted to a lower position, as shown by a dotted line, when the switch is set for the siding.

The switch control relay W is preferably a direct current polarized relay having polarized armatures that remain in the position to which they were last moved by the energization of the relay until the relay is energized by current of reverse polarity. This relay, when energized with normal polarity of current moves its armature to a normal position which selects the normal operating circuits (not shown) for the switch machine SM to position. the switch for the main line. When relay W is energized with reverse polarity of current, then its polarized armatures are moved to a reverse position to select the reverse operating circuits for the switch machine SM thereby shifting the switch for trafiic to the siding. In the Fig. 1, the normal position of the armatures of relay W is the lefthand position, that is, the position as shown in the figure, and the reverse position is the righthand position, or the position opposite that shown in the figure.

The switch control relay W is controlled by means of the code relays BY and 6X. With the normal code relay BX energized and its armatures l5 and I6 lifted, as shown in Fig. 2, then current is supplied to the relay W from the positive terminal B, through a back contact of armature l8 of the relay BY, front contact of armature l5 of relay 6X, wire l9, winding of relay W, wire 2|, armature 22RM of an approach locking relay RM to be described later, armature ZSLM of a second approach locking relay LM, wire 24, armature 25 of the track relay TR, wire 26, armature I6 of relay 6X, armature 21 of relay BY, and tothe negative terminal C. The polarity of the current thus supplied is such as to move the polarized armatures of the relay W to the left-hand position to bring about an operation of switch W to its normal position. In the event the code relay BY is energized and the relay 6X remains deenergized, it is apparent, by an inspection of Fig. 2, that the current supplied to the relay W is of a reverse polarity. Current of the reverse polarity causes relay W to shift its armatures to the righthand position to bring about an operation of switch W to its reverse position.

The switch repeater relay KR is preferably a direct current polarized relay and is controlled jointly by the switch SW and the switch control relay W. With the switch locked normal and relay W also in its normal position, current is supplied to the relay KR from the positive terminal 13', over controller l2, wire 28, winding of relay KR, wire 29, polarized armature 30, wire 3!, and controller M to the negative terminal C. With switch SW and relay W each in the reverse position, then the relay KR is supplied with current of reverse polarity from positive terminal B, controller I3, wire 32, armature 30 in the righthand position, wire 29, coil of relay KR, wire 28, and controller l2 to the negative terminal C. With the relay KR energized by current of the polarity corresponding to the normal position of the switch SW, its polarized armatures occupy the left-hand position, and with the switch SW reversed, then the polarized armatures of the KR relay occupies the right-hand position. It is evident that with the relay KR energized with either polarity of current that its neutral armatures are lifted.

The direction of traific over the switch SW is selected by the two trafiic governing directional relays RH and LH, which are repeaters of the signal code relays 'IY and 1X, respectively. With relay 6X energized so that the switch is set for the main line and the relay 'IY also energized, current for energizing the relay RH is supplied from the positive terminal B through armature 33 of relay TY in its raised position, armature 34 of the relay 1X, wire 35, back contact of the armature 36 of the opposing directional relay LH, wire 31, winding of the relay RH, wire 38, armature ZB of the track relay TR, wire 39, neutral armature 4|] of the KR relay, polarized armature 4|, wire 42, armature I! of the code relay GK, and then to the negative terminal C. Once the relay RH is energized, a stick circuit that branches from the wire 39, through front contact of its own armature 43 and to the negative terminal C, is closed. Also, for purposes to be brought out later, the network of control circuits for the RH relay includes two shunt paths from wire 38 to the wire 39 around armature 20, one of which includes the armature 45 of the code relay CS, and the other of which includes the armature 65 of a RHG relay which is associated with the signal R2 as will later appear. In the event the code relays TX and 6X are energized, then current is supplied to the directional relay Ll-I by a circuit that extends from the positive terminal B, through the armature 33 of the relay 'IY, front contact of armature 46 of the relay IX, wire ll, back contact of armature H of the opposing directional relay RH, wire 49, winding of the relay LH, wire 50, wire 38, armature 20', wire 39, armature 4|], polarized armature 4!, wire 42, and armature I! of the code relay 6X to the common terminal C. In the control network for this relay there is provided a stick circuit that branches from the wire 39, through its own armature 5!, and to the negative terminal C. There is provided also for this relay LH two shunt paths around the armature 20 one of which includes the armature 44 and the second of which includes the armature SZ of a relay LHG associated with the signal L2. It is here noted that in the event the relay BY is energized so that the switch is reversed and the armature 4! of the relay KR is reversed, that the circuit for either the relay RH or LH is completed from armature A! by wire 53 and armature 54 of relay fiY to the negative terminal C.

The relays RH and LH each govern the controlling circuit for the wayside signals R2 and L2, respectively. The circuit for energizing the winding 5 of the mechanism a of signal R2 is supplied through the one branch of a route circuit network that extends from the positive terminal B through armature 55 back contact of the armature 56 back contact of armature 51 of a time element relay to be later described, neutral armature 58 armature EQ when relay RH is energized, back contact of armature BD of the approach locking relay RM to be later described, polarized armature EH armature BZ armature 63 wire 65, winding 5, wire 65, armature 66 of relay RH, and to the negative terminal C. It is to be noted among other things that in order to energize the winding 5 of signal mechanism a, the directional relay RH must be energized, and that the approach locking relay RM must be deenergized to close the back contact of armature BIJ The latter insures that the switch SW has been properly positioned and locked for the main track before the signal R2 can be, cleared due to the fact that the relay RM controls the operation of the switch control relay W by the front contact of its armature 22 Likewise the directional relay LH governs the circuit to the winding 5 of the signal mechanism a for the signal L2. This branch of the route circuit extends through the network from the positive terminal B, armature SI back contact of the armature 59 of the opposing directional relay RH, armature ES armature lil armature ES with relay LH energized, back contact of armature 68 of the approach locking relay LM, armature ESS polarized armature TE armature 'H wire 12, winding 5, wire 13, armature 14 of relay LH, and to the negative terminal C. Attention is directed to the fact that the energizing of the mechanism a of signal L2 requires that the approach locking relay must first be deenergized to close the back contact of armature 68 and that to move the switch requires the relay LM be energized to close the front contact of the armature 23 Current for energizing the winding 5 of the mechanism b of the signal L2 is obtained through the network from positive terminal B, through armature BI armature 59 armature 53 armature 51, front contact of armature 56 back contact of armature 58 armature 59 polarized armature TU in its reverse position indicating that the switch SW is set for the siding, wire 75, winding 5 of the mechanism 2), wires 15 and 73, and armature M to the negative terminal C. Thus in order to clear the mechanism 2) of L2, the approach locking relay LlvI must be first energized to permit proper selecting of the relay W and then after the switch SW has been positioned and locked, the relay LM must become deenergized to close the back contact of the armature 68 The winding 5 of the call-on signal mechanism c of signal R2 receives current from a positive terminal B over the same branch of the net- Work as that traced for the winding 5 of mechanism a of R2 up to and including the back contact of the armature GG of approach locking relay RM, then along wire 18, armature 19 of the code relay CS, wire 85, winding 5, wire 55, and armature 66 to the negative terminal C. The closing ofthis circuit, however, will not clear the mechanism 0 unless the mechanism a is at stop so as to close at its controllers 6 and l the circuit for energizing the winding 5 of mechanism 0 as will be readily understood by an inspection of Fig. 1. Again it is to be noted that in order to clear the mechanism 0 of R2, it requires that the approach locking relay RM be first deenergized to close the back contact of the armature SU and furthermore that the operator energizes the relay CS in addition to the relay 1X. In order to clear the signal R211 to permit a train moving from the siding, the operator must energize the relays 5Y and TX to effect the reversal of the switch SW and the energizing of the relay RH. Current in this instance is supplied to winding 5 of mechanism d from the positive battery B, through the branch of the network that includes armature 55 armature 56 armature Sl armature ES armature 59 with relay RH energized, armature GB in its down position, armature BI reversed, wire 71, winding 5 of signal RZd, Wire 65, and armature 65 to the negative terminal C. The winding 4 of this signal RZd is energized only upon the condition that the mechanisms at and c of R2 are both in the stop position as will be understood by an inspection of Fig. 1. Once again it is to be noted that in order to clear the signal R2d, it requires that the approach locking relay RM be deenergized to close the back contact of armature SU The winding 5 of the mechanism 0 of the signal L2 is energized with the switch in either position in the event the operator energizes both the relay IX, and the relay CS. Under this condition, winding 5 of 0 receives current from the positive terminal B, through the branch of the network that includes til EB SS ST 56 raised with relay LI-I energized, armature BB down, wire 8|, armature 82 of relay CS, wire 83, winding 5, wires 85, "I6 and 13, and armature 14 to the negative terminal C. Again we note that in order to clear this signal mechanism, it requires that the approach locking relay LM be deenergized in order to close the back contact of the armature 68 The signal R3 is controlled by the track relay R2TR and the line relay RD. The line relay RD is controlled by the position of the signal R2. The circuit for relay RD extends from the positive terminal B, through controller 5 in engagement with contact II indicating that mechanism a is in the proceed position, wire 85, coil of relay RD, and to the negative terminal C. With track relay RZTR and the line relay RD both energized the current supplied to the winding 5 of the mechanism a of the signal R3 is of a polarity that causes the signal to display proceed, while with the track relay RZTR energized, and the line relay RD deenergized, current of reverse polarity is supplied to the winding 5 to cause the signal R3 to display a caution indication. The signal L3 is controlled in a manner similar to that just described ior the signal R3.

Two relays designated by the reference characters RHG and RGP are associated with the signal R2. The relay RHG is normally deenergized, it being energized by a circuit that extends from the positive terminal B, through the lower contacts 8 and 9 of the controllers 6 and 1, respectively, of the mechanism a, the controller 6 of mechanism 0 in engagement with the contact 8 and the controller I of c in engagement with the upper contact ID, orif I engages contact 9 then through controller I of mechanism d in engagement with its contact I 9, wire 81, winding of relay RI-IG and to the negative terminal C. This circuit is normally open and is closed only when either mechanism 0 or 03 is cleared. The function of this relay will appear later on in the description. The relay RGP checks the stop position of the signal mechanisms a, c and d inasmuch as its circuit passes from the positive terminal B through the stop position of each of the controllers of these mechanisms as Will be readily understood by an inspection of Fig. 1, then along wire 88, winding of RGP and to negative terminal C. The signal L2 has associated with it two relays LI-IG and LGP which are controlled respectively in a manner similar to that just described for the relays RHG and RGP. It will be readily apparent that a signal for only one direction can be cleared at a time, for the reason that the route circuits for each direction each includes a front contact of the relay RGP or LGP controlled by the signals for the opposite direction, and for the additional reasons that the circuits for relays RH and LH are interlocked, and that each route circuit includes a front contact of one and a back contact of the other of these relays.

Each direction,0f traffic is provided with a normally energized approach locking stick relay and an approach control relay. The approach control relay RA associated with trafiic from the left to the right is normally energized by a circuit that extends from the positive terminal B at the signal location R3 through the armature I04 of the track relay R3TR for the approach section R3T, armature I05 of the track relay TZTR of the approach section RZT, line wire I06, coil of relay RA, and to the negative terminal C. The approach control relay LA associated with trafiic from the right to the left in the figures is normally energized by a circuit that extends from the positive terminal B at the signal location L3 and which circuit includes the armature I01 of relay L3TR and armature I08 of the track relay L2TR.

The approach locking relay RM associated with traflic from the left to the right is normally retained energized by a stick circuit that may be traced from the positive terminal B at the sig- [wil nal location R3 through controller 6 in engagement with contact 8, controller 'I in engagement with either contact 9 or contact Ill, wire 89, armature 9!) of the relay RGP, wire 9|, back contact of the armature 92 of the relay RI-I, wire 93, front contact of its own armature 94, winding of the relay RM, and to negative terminal C. This relay RM is provided with a pick-up circuit that extends from the positive terminal B at the signal R3 over the same circuit as before traced up to wire 93, and then along wire I2'i, armature 95 when relay TR is deenergized, wire 96, neutral armature 91 of the switch repeater relay KR, polarized armature 98 in its normal position, wire 99, armature I96 of approach control relay RA, wire IiiI, winding of relay RM, and to the negative terminal C. This pick-up circuit also has a branch path that extends from the wire I21, through the armature I02 of the time element relay TE, wire I03 to the wire IIII, and then as before traced. It will be noted that this approach locking relay RM will become deenergized whenever the directional control relay RH is energized and that once the relay RM is deenergized, it can be reenergized only in the event the approach track sections R3T and R2T are vacated so that the approach control relay RA is energized, that the detector track relay TR is shunted to drop the armature 95 that the switch is set in the normal position and that the directional relay RI-I has been opened either in the network or by the deenergizing of the code relay EX.

The approach locking relay LM associated with traffic from the right to the left is controlled by circuits similar to those described for the approach locking relay RM. The normal stick circuit for the approach locking relay LM extends from the positive terminal B at the signal L3,

through controller I in engagement with contact 9, controller 6 in engagement with either contact 8 or contact II, line wire I39, armature I!!! of LGP, wire II I, armature IIZ of the directional relay LI-I, wire I I3, front contact of its own armature II l, winding of relay LM, and to the negative terminal C. The pick-up circuit for this re-- lay LM extends from the same positive terminal B over the same circuit as before traced up to the wire IE3, and then along the wire I I5, armature lili of the track relay TR, wire I, armature N8 of the relay LA, wire II 9, winding of relay LM, and to the negative terminal C. There is a shunt path for this pick-up circuit that branches from the wire II5, through the armature i2il of time element relay TE, wire I2I to wire I iii and then as before traced, the function of which will be shortly described.

Associated with the control of the approach locking relays RM and LM is a time element relay TE. This time element relay TE may be of any of the well known types and in this instance it is normally deenergized and will close the front contacts of its armatures Hi2 and I some predetermined time after its energizing circuit has been closed. The energizing circuit for this relay may be supplied with current from positive terminal B at the signal R3 or at the signal L3.

In the event trafiic is from left to right, the cir-,

cuit for energizing TE extends from the positive terminal 13 at R3, through either the caution or stop position of the controllers 5 and I of the sig nal mechanism a of R3, wire 89, armature 90 of RGP, wire BI, armature 92, wire 93, armature 9a of relay RM in engagement with its back contact, wire I22, armature I23, armature IZ I armature I25 coil of relay TE, and to the negative terminal C. In the event traffic is from the right to the left, then current is supplied to the time element relay TE from the positive terminal B at the signal location L3, through either the caution or stop position of the controllers 6 and l of the mechanism a of L3, line wire IE9, armature IIO, wire III, armature H2, wire H3, armature I I4 down in engagement with its back contact wire I 26, wire I22, and then as before traced.

Having pointed out the several circuits and the diiferent apparatus that are included in our invention, we will now describe its operation. It will be understood that all apparatus of Figs. 1 and 2 is shown in its normal position. We shall first assume that the operator energizes the code relay 'iY with the result that the directional relay RH is energized to close its front contacts. The lifting of the armature S2 of the relay RH opens the stick circuit of the approach locking relay RM and that relay becomes deenergized. The closing of the front contacts of the armatures 66 and 59 of the relay RH and back contact 88 of the relay RM supplies current to the mechanism a of the signal R2, and this signal is cleared. The clearing of the mechanism a of the signal R2 energizes the relay RD, and the signal R3 is then moved into its proceed position. It will be seen that before the signal R2 can be cleared, it requires that the approach locking relay RM must be released and with relay RM down to open the armature 22 the switch control relay W can not be changed. Thus it is apparent that relay RM must be normally energized in order to effect a movement of the switch and that it must be deenergized to effect a clearing of the signal R2. It follows that it is safe to at once select a reverse position of the switch SW by deenergizing the normal code relay GK and energizing the reverse code relay GY, in view of the fact that as long as approach locking relay RM is deenergized, switch SW will not at once follow the energizing of the reverse code relay EEY. The relay W will respond to the energizing of the code relay SY only when its control circuit has been closed at the armature 22 which will take place only when the approach locking relay RM has been reenergized. We will now assume that a train approaches the signal R2 after this signal has been cleared. The train shunting either the track relay R3TR or R2TR of the approach track sections opens the circuit to the approach control relay RA and the armatures of that relay drop. In the event the track relay TR of the detector track section should be momentarily shunted during the period the train is approaching the clear signal R2, the shunting of TR would open the circuit of the relay RH at its armature 2II resulting in the signal R2 being set at stop position. The signal R2, assuming the stop position, reenergizes the relay RGP, however, the approach locking relay RM will not be reenergized due to the fact that its pick-- up circuit includes the contact Hm, now open, 7

of the approach control relay RA. Thus in our system a momentary shunt of the detector track circuit does not result in .a loss of the approach locking that would otherwise permit the relay W to reverse and start a movement of the switch under the condition where a reverse control has been stored.

With the train approaching a clear signal at R2, let us assume that relay RA has become falsely energized in some manner so that its armature l 60 is up. Should the attempt be made to display a stop signal at R2 at the moment when RA is falsely up, the approach locking relay RM will not be reenergized due to the fact that we have inserted in the pick-up circuit of RM a back contact of the armature of the track relay TR. Thus we have two contacts (um and 95) that must function in regular order of train movements to reenergize the approach locking relay RM and release the approach locking. Again let us assume that with RA falsely closed, track relay TR is momentarily shunted during the interval a train is approaching a clear signal at R2 under the condition where a reverse control has been stored by energizing the reverse control relay GY. The switch control relay W will still not operate due to the fact that its control circuit includes a front contact of the armature 25 of the track relay TR. Thus in our invention, we have provided against any false movement of the switch while a train is approaching a clear signal up to three irregularities all of which must happen at the same instant. In other words this combination of control provides a continuous check on the integrity of the approach locking and insures a minimum chance of a false operation of the switch occurring at a time when a reverse movement of the switch has been stored.

The approach locking relay LM associated with traffic from the right to the left functions in the same manner for a train approaching switch SW from the right and provides the same protection against a false movement of the switch as that described for the approach locking relay RM.

In centralized traffic control systems, it is desirable at times to employ a single code to in sequence operate the switch and clear the signal governing traffic over the route corresponding to the operated position of the switch. It is necessary under such conditions to insure that there is an agreement between the controlling relays for the switch and signals so that the signal control can not function ahead of the control of the switch. Let us assume that it is desirable to move a train past the signal L2 into the siding, and that the relays BY and 1X are energized by a single code. At the instant the code is received, the KR relay is, of course, normal, however, the relay LI-I can not at once pick-up, because its circuit that includes the normal position of the armature ll of the relay KR is cut to negative terminal C through the armature ll of the relay EX which is now deener-gized, and the circuit for LH that is closed to the negative terminal C through the armature 5 1 of the relay ESY which is the relay now energized, includes the reverse contact of the armature 4| of the relay KR. Thus the relay LH is not energized until the switch SW has functioned and has reversed the relay KR.

If after the mechanism 2) of the signal L2 has been cleared for a movement to the siding, as just described, the operator transmits a second code to route a following train over the switch in its normal position, which code will deenergize the relay GY and reenergize the relay 6X, the signal governing the first train will not be interfered with. This is because we have provided a stick circuit for the relay LH so as to retain the mechanism 2) of signal L2 in its clear position until the first train has advanced to occupy the detector track section i T even though there now exists a disagreement between relays BY and KR.

This stick circuit for the relay LI-I, while before pointed out, will again be traced and we find that it extends from the positive terminal B, through armature 33 of relay TY, armature 46 of relay EX, wire 41, armature 48 wire 49, winding of relay LI-I, wire 59, wire 38, armature ZB front contact of the armature El and to the negative terminal C. This stick circuit insures that the signal L2 is retained in a clear position for a movement into the siding until such time as the train occupies the detector track circuit.

In a similar manner the directional relay RH is provided with a stick circuit which includes front contact of its own armature 43 The call-on mechanism 0 of either R2 or L2 or the siding signal R211 may be cleared even though the detector track relay TR is shunted for some reason by a code that selects the code relay CS in addition to selecting either the code relay W or 1X as the case may be. With the code relay CS energized to close the front contact of its armature 44 the control circuit for either the relay RI-I or LH is closed around the armature 28 of the track relay TR.

Furthermore, in order to prevent the call-on signal mechanism 0 of either R2 or L2 or the signal R2d being set at stop, by the track relay TR being shunted to open the front contact of its armature 26 at a time when the code relay CS is not energized, the by-paths through the armatures 45 and EZ are provided. Let us assume the call-on mechanism 0 of R2 has been cleared as a result of a code that selects relay 'lX but not CS. Once the mechanism 0 of signal R2 clears to bring its controller i into engagement with the contact II], the relay RHG picks up to close the front contact of its armature 45 With armature 45 up then this call-on signal 0 will be retained in the clear position until a diiferent code is received even though the track relay TR becomes shunted. Again let us assume that traflic is from the siding towards the right in the figures, and that the code relay TY has been energized to energize the directional relay RH and in turn the signal R2 cleared. As soon as the signal R201 clears, the relay RI-IG picks up to close the contact of the armature 45 due to the fact that its controller 1 is now in engagement with its contact 10. In a similar manner the relay LI-IG functions to control the signal mechanism c of the signal L for traflic from the right to the left.

Inthe event that a route has been set up and a train has entered the approach track section and then it becomes necessary to change the position of the switch before the train passes beyond the limits of the route, the time element relay TE is provided. Let us assume that the signal R2 has been cleared and a train approaching the signal from the left has entered the section R3T and that it then becomes necessary to change the position of the switch. The deenergizing of the relay RH sets signal R2 at stop and with relay RH down, the energizing circuit for time element relay TE associated with traflic from the right to the left is closed and the relay TE set into operation. After a predetermined time interval the relay TE closes its contacts, the time interval being so chosen as to insure that the approaching train will have time to be over the switch and gone, or to allow it to come to a stop to the rear of signal R2. With relay TE closing its contacts, the pick-up circuit for the approach locking relay RM is completed through the front contact of the armature Hi2 and the approach locking relay RM reenergized. With relay RM up, then the switch SW may be reversed as under normal conditions, It will be understood that the time element relay TE functions in a like manner for a train approaching the signal L2 from the right.

As stated earlier in the specification, while the wayside signals disclosed are of the Searchlight type, our invention is equally adapted to any other type of signals, also that while we have disclosed a system making use of code relays, our invention is equally adapted to a system that relies for control upon the movement of controllers operated by a lever of a tower machine or where the control is automatic.

Such a system as here disclosed insures against a false operation of the switch up to three irregularities all of which must occur at the same instant, that the operation of the switch and signal will take place in the proper sequence and that the storing of a code will not affect a route set up until the signal has been accepted by a train and the route vacated.

Although we have herein shown and described only one form of railway trafiic controlling apparatus embodying our 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 our invention.

Having thus described our invention, what we claim is: v

1. In combination, a railway switch, a signal to govern trafiic over the switch, a normally deenergized traffic governing relay, a normally energized approach locking relay, means controlled from a remote point to energize said traffic governing relay and to deenergize said approach locking relay, a circuit effective with said traffic governing relay energized and said approach locking relay deenergized to clear said signal, and means to operate the switch ineffective to move the switch as long as said approach locking relay is deenergized.

2. In combination, a railway switch, a signal to govern trafiic over the switch, a normally deenergized traihc governing relay, a normally energized approach locking relay, means controlled from a central oifice to energize said traflic governing relay and to deenergize said approach locking relay, a circuit rendered eifective with said traffic governing relay energized and said approach locking relay deenergized to clear the signal, means to operate the switch ineffective to move the switch as long as said approach locking relay is deenergized, and a traffic controlled circuit to reenergize said approach locking relay.

3. In combination, a railway switch, a first track section remote from the switch, a second track section adjacent the switch, a signal to govern traffic over the switch, a normally energized stick relay, means controlled from a central office for rupturing the stick circuit of said stick relay, a circuit rendered efiective by the deenergizing of said stick relay to clear the signal, a pick-up circuit for said stick relay to reenergize said stick relay in response to a train traversing successively the first and second track sections, and means for operating said switch effective to move the switch only when said relay is energized.

' 4. In combination, a railway switch, a first track section remote from the switch, a second track section adjacent the switch, a signal to govern traffic over the switch, a trafiic governing relay, a normally energized stick relay, means controlled from a central office for energizing said trafiic governing relay and to rupture the stick circuit of said stick relay, a circuit rendered effective by'the energizing of said traffic governing relay and the deenergizing of said stick relay to clear said signal, a pick-up circuit for said stick relay to energize said stick relay in response to a train traversing said first and second track sections and the deenergizing of said traffic governing relay, and means to operate said switch effective to move the switch only when said stick relay is energized.

5. In combination, a railway switch, a signal to govern traflic over the switch, a first track section remote from the switch, a second track section adjacent the switch, a switch controlling relay to control the operation of the switch; means to render at times said switch controlling relay ineffective to control the switch, including an approach locking stick relay; a trailic governing relay controlled from a remote point to rupture the stick circuit of said stick relay, a circuit rendered efiective by the deenergizing of said stick relay to clear the signal, and a pick-up circuit to energize said approach locking relay in response to a train entering and vacating successively the first and second track section to restore the control of said switch controlling relay.

6. In combination, a railway switch, a signal to govern traffic over the switch, a switch controlling relay to control the switch, a signal governing relay to govern the signal, a first remote controlled relay to control both the switch controlling relay and the signal governing relay, a second remote controlled relay to control the signal governing relay only, and a stick circuit for said signal governing relay to retain said relay energized and the signal cleared irrespective of said first remote controlled relay.

'7. In combination, a railway switch, a signal to govern traffic over the switch, a switch controlling relay to control the operation of the switch, a signal governing relayto govern the signal, a remote controlled relay to control both the switch controlling relay and the signal governing relay, and a stick circuit for said signal governing relay to retain said relay energized and the signal cleared irrespective of the condition of said remote controlled relay.

8. In a centralized trafiic control system for railways, a track switch, a signal to govern traffic over the switch, an approach locking circuit, means rendered effective to move the switch only when said approach locking circuit is closed, means rendered efiective to clear the signal only when the approach locking circuit is open, means controlled from a central ofiice to open said approach locking circuit and thereby clear said signal, and means responsive to a train advancing past the said signal and switch to close said approach locking circuit.

9. In a centralized traffic control system for railways, a track switch, a first and a second signal to govern traflic over said switch, a signal control relay to control said signals, a track circuit including said switch, a despatcher controlled means, means controlled jointly by said track circuit and said despatcher controlled means to energize said signal control relay to clear said first signal, and means to at times energize said relay by said despatcher controlled means irrespective of said track circuit to clear said second signal.

10. The combination with a track switch of a locking relay railway system, of a switch machine for operating said switch, a signal associated with said switch for governing movement of traflic over said switch, a locking relay which if deenergized prevents operation of said switch, a control relay for controlling said signal to permit clearing of said signal only when said control relay is energized, a time element device rendered active to energize said locking relay a predetermined time after being energized, a circuit for said time element device including a back contact of said control relay, and a circuit for said signal including a normally closed contact of said time element device.

11. In combination with a stretch of railway track, a signal governing trafiic over said stretch, a stick relay controlling said signal, means controlled from a remote point for energizing said stick relay, a second relay, means controlled from ;a remote point for selectively energizing or deenlay is deenergized for releasing said stick relay when said stretch becomes occupied.

12. In combination, a railway switch, a signal to govern traific over the switch, a locking relay to control the operation of the switch and of the signal, said relay being arranged to permit operation of the switch only when energized, and to permit the signal to clear only when deenergized, means controlled by the movement of a train past the signal to cause the signal to as- ;sume its most restrictive condition and to energize said relay when it assumes said condition,

and manually operable means for releasing said relay to permit the signal to be cleared, whereby the switch is locked against operation unless the -signal is in its most restrictive condition and the signal is prevented from clearing unless the switch is locked.

13. In combination, a railway switch, a signal to govern traiiic over the switch, a locking relay,

,a circuit for said relay controlled by the signal and closed only when the signal displays its most restrictive indication; a circuit including a front contact of said locking relay for controlling the switch, a circuit including a back contact of said for clearing the signal, and manually operable means for releasing the locking relay to permit the signal to be cleared.

14. In combination, a railway switch, an approach track section remote from the switch, a detector track section including the switch, a normally energized stick relay, means controlled from a central office for rupturing the stick circuit of said stick relay, a circuit rendered effective by the deenergizing of said stick relay to clear the signal, a pickup circuit for said stick relay closed to reenergize said relay when the detector track section is occupied and the approach track section is not occupied, and means for operating said switch efiective to move the switch only when said relay is energized and the detector track section is not occupied.

15. In combination, a railway switch, an approach track section remote from the switch, a detector track section including the switch, a normally energized stick relay, means controlled from a central office for rupturing the stick circuit of said stick relay, a circuit rendered efiective by the deenergizing of said stick relay to clear the signal, a circuit for said stick relay closed to reenergize said relay only when the signal is in its most restrictive condition, said circuit having one branch closed when the detector track section is occupied and the approach track section is not occupied, another branch including a time controlled contact and a third branch including a front contact of said relay, and means for operating said switch effective to move the switch only when said relay is energized and the detector track section is not occupied.

16. In combination, a railway track switch, switch control means, signal control means, a stick relay, a pickup circuit for said relay closed only when the signal control means is energized, and the switch and the switch control means are in corresponding positions, a stick circuit for said relay closed when the relay is picked up and the signal control means is energized; a signal for governing traffic over the switch, and a circuit for clearing the signal including a front contact of the stick relay.

1'7. In combination, a railway track switch, switch control means, signal control means, a stick relay, a pickup circuit for said relay closed only when the signal control means is energized, and the switch and the switch control means are in corresponding positions, a stick circuit for said relay closed when the relay is picked up and the signal control means is energized; a signal for governing trafiic over the switch, a circuit for clearing the signal including a front contact of the stick relay; and an operating circuit for the switch, controlled by said switch control means, and closed only when said signal is in its most restrictive condition.

18. In combination, a railway track switch, switch control means, signal control means, a stick relay, a pickup circuit for said relay closed only when the signal control means is energized, and the switch and the switch control means are in corresponding positions, a stick circuit for said relay closed when the relay is picked up and the signal control means is energized; a signal for governing traflic over the switch, a circuit for clearing the signal closed only when the stick relay is energized, and an operating circuit for the switch controlled by said switch control means, and closed only when said stick relay is deenergized.

19. In combination, a railway track switch, switch control means for operating the switch, a stick relay, a pickup circuit for said relay closed only when the switch and the switch control means are in corresponding positions, a stick circuit for said relay independent of the switch and of the switch control means, a signal for governing traffic over the switch, a circuit for clearing the signal closed only when the stick relay is energized, and manually controllable means for controlling the pickup and stick circuits of said relay to control said signal.

20. In combination, a detector section of railway track including a track switch, switch control means, a stick relay, a pickup circuit for said relay closed only when the detector section is unoccupied and the switch and switch control means are in corresponding positions, a stick circuit for said relay closed, when the relay is picked up and the detector section is unoccupied; a signal for governing traffic over the switch, a circuit for clearing the signal including a front contact of the stick relay, and an operating circuit for said switch controlled by said switch control means and closed only when said detector section is unoccupied and said signal is in its most restrictive condition.

lay is energized, and an operating circuit for said switch controlled by said switch control means and closed only when said detector section is unoccupied and said stick relay is deenergized.

22. In combination, a section of railway track having a track relay, a main signal and a call-on signal for governing traffic through said section,

a signal relay, a circuit for clearing the main signal, closed only when the signal relay and the track relay are energized, a first circuit for the signal relay including a front contact of the track relay and a manually controllable contact, a second relay, a circuit for clearing the call-on signal closed only when the signal relay and the second relay are energized, a second circuit for the signal relay including a front contact of the second relay and said manually controllable contact, manually operable means for controlling said second relay, and means for preventing the clearing of the call-on signal except when the main signal is in its most restrictive condition.

23. In combination, a section of railway track having a track relay, a main signal and a call-on signal for governing traffic through said section, a signal relay, a circuit for clearing the main signal closed only when the signal relay and the track relay are energized, a circuit for the signal relay including a front contact of the track relay and a manually controllable contact, a second relay, a circuit for clearing the call-on signal closed only when the signal relay and the second relay are energized, a second circuit for the signal relay including said manually controllable contact but independent of the track relay and closed when the call-on signal has been cleared, and means for preventing the clearing of the call-on signal except when the main signal is in its most restrictive condition.

24. In combination with a stretch of railway track, a signal governing trafiic over said stretch, a stick relay controlling said signal, a track relay for said stretch, means for deenergizing said track relay when the stretch is occupied by a train, a first relay and a second relay manually controllable from a point remote from said signal, a pickup circuit for the stick relay including a front contact of said first relay, a stick circuit for the stick relay including the winding and a front contact of said stick relay, and in multiple, front contacts of said track relay and of said second relay, and an energizing circuit for said signal including front contacts of said stick relay and of said track relay.

25. In combination, a railway switch having a normal and a reverse position, a polarized relay controlled by said switch arranged to occupy its normal position when the switch is normal and to occupy its reverse position when the switch is reversed, a normal and a reverse remote controlled switch controlling relay to govern the switch, a repeater relay, circuit means to energize said repeater relay only in the event the polarized relay controlled by the switch is in its normal position when the normal switch controlling relay is energized or is in its reverse position when the reverse switch controlling relay is energized, and a signal circuit to govern traffic over the switch closed only when said repeater relay is energized.

26. In combination, a stretch of track, a traffic device included within said stretch of track and operable for at times changing the continuity of said stretch of track, signals for governing traffic in both directions over said stretch of track,

a circuit extending between two traflic governing relays respectively associated with the opposite ends of said stretch of track, a current source at each end of said circuit for supplying current to said circuit but normally disconnected therefrom, a manually controlled relay associated with each end of said circuit, a contact included in said circuit which contact is closed when and only when said traffic device is locked to prevent its operation, means governed by each said manually controlled relay when energized to connect the associated current source with said circult, and means governing said signals by said traflic governing relays so as to permit traffic to move through said stretch of track in a direction determined by the end at which said circuit is supplied with current.

27. In combination, a stretch of track, a traffic device included within said stretch of track and operated for at times breaking the continuity of said stretch of track, signals at opposite ends of said stretch for governing traific in opposite directions over said stretch of track, a circuit extending between two trafiic governing relays respectively associated with the opposite ends of said stretch of track, a current source at each end of said circuit for supplying current to said circuit but normally disconnected therefrom, a manually controlled relay associated with each end of said circuit, a contact included in said circuit which contact is closed only when the continuity of said stretch is completed by said traflic device, a second contact included in said circuit which second contact is closed when and: only when said traffic device is locked to prevent its operation, means governed by each said manually controlled relay when energized to connect the associated current source with said circuit, and means for clearing the one of said signals at the end ofsaid stretch having both its associated said trafiic governing relay and said manually controlled relay energized so asto permit traffic to move through said stretch of track in a direction determined by the end at which said circuit is supplied with current.

28. In combination, a stretch of track, a trafllc device included within said stretch of track and operated for at times breaking the continuity of said stretch of track, signals at opposite ends of said stretch for governing traflic in both directions over said stretch of track, a circuit extending between two trailic governing relays respectively associated with the opposite ends of said stretch of track, a current source at each end of said circuit for supplying current to said circuit but normally disconnected therefrom, a manually controlled relay associated with each end of said circuit, a contact included in said circuit which contact is closed only when the continuity of said stretch is completed by said traffic device, a second contact included in said circuit which second contact is closed only when said trafiic device is locked to prevent its operation, means governed by each said manually controlled relay when energized to connect the associated current source with said circuit, means for clearing the one of said signals at the end of said stretch having both its associated said tramc governing relay and said manually controlled relay energized so as to permit trafiic to move through said stretch of track in a direction determined by the end at which said circuit is supplied with current, and means effective upon the energization of one of said manually controlled relays for closing said second contact.

29. In an interlocking system for railroads, a stretch of railway track, a track switch in said stretch, signals for governing trafiic in opposite directions over said stretch, a route circuit including a contact assuming a position corresponding to the position of the switch, a relay at each end of said circuit, means for applying to said circuit either of two polarities at each end, a looking contact associated with said track switch and included in said circuit for allowing the circuit to be completed only when the track switch is locked, and means for clearing said signals dependent upon the energization of said relays.

30. In an interlocking system for railroads, a stretch of railway track containing a track switch, signals for governing trafiic in opposite directions over said stretch, a control contact for each of said signals operable to clear or stop position, means rendered eiiective when any one of said control contacts is moved to a clear position for locking said track switch against operation, a route circuit having current flowing therein only when said track switch is locked and only when a control contact is moved to its clear position, and means responsive to the fiow of current in said route circuit for clearing the signal corresponding to such control contact.

31. In an interlocking system for railroads, a track layout including a track switch, means for at times locking said track switch against operation, contacts controlled by the track switch in accordance with its position, a plurality of wires adapted to be interconnected by said contacts to establish a route circuit corresponding to each trackway route established by said track switch, a signal at each end of each trackway route, energizing means at each end of each route circuit for energizing such route circuit when established, interlocking means preventing the energizing means at one end of a route circuit from functioning when the energizing means at the other end of said route circuit is effective, means preventing the establishment of any route circuit unless said track switch is locked against operation, and means for energizing the signal at one end or the other of an established route circuit depending upon the end at which such circuit is energized.

32. In an interlocking system, the combination of a track layout containing a plurality of routes each including a track switch, a locking relay for preventing the operation of said switch when deenergized, a plurality of route circuits each corresponding to one of said routes and including a conductor for each portion of the route and a contact assuming a position corresponding to the position of the track switch, each said route circuit also including a back contact of said locking relay, and a signal at each end of each route controlled by the route circuit corresponding to such route.

33. In an interlocking system, the combination with a track layout including a track switch for arranging different trafiic routes, switch indication contacts controlled in accordance with the position of the track switch, a locking relay which if deenergized prevents power operation of the track switch, a route circuit for each of said routes including said indication contacts and a back contact of said locking relay, and means for energizing each route circuit by current of which the relative direction depends upon the direction in which traffic shall be permitted to move over such route.

34. In an interlocking system, the combination with a track layout including a track switch for arranging different trafi'ic routes, switch indication contacts controlled in accordance with the position of the track switch, a locking relay which if deenergized prevents power operation of the track switch, a route circuit for each of said routes including said indication contacts and a back contact of said locking relay, means for energizing each route circuit by current of which the relative direction depends upon the direction in which trafiic shall be permitted to move over such route, and manually operable means for deenergizing said locking relay.

35. In combination, a track layout including a track switch for establishing any one of a plurality of routes, a switch machine for controlling said track switch, a polar control circuit for operating said switch machine to a normal position and to the reverse position respectively when energized by current of one polarity or the. other, a locking relay having front contacts included in said polar control circuit, whereby said switch machine cannot be operated to either position unless said locking relay is energized, a signal for governing trafiic over one of said routes, and a circuit for clearing said signal including back contacts of said locking relay closed only if said locking relay is deenergized.

36. In combination, a track layout including a track switch for establishing any one of a plu-' rality of routes, a switch machine for controlling said track switch, a polar control circuit for operating said switch machine to a normal position and to the reverse position respectively when energized by current of one polarity or the other, a locking relay having front contacts included in said polar control circuit, whereby said switch machine cannot be operated to either position unless said locking relay is energized, a signal, for governing trafiic over one of said routes, a circuit for clearing said signal including back contacts of said locking relay closed only if said locking relay is deenergized, and means which if manually operated to a particular position permits said signal to be conditioned for clearing and breaks the energizing circuit for said locking relay the dropping of which locking relay in turn allows clearing of said signal.

37. In combination, a track layout including a track switch for establishing any one of a plurality of routes, a switch machine for controlling said track switch, a polar control circuit for operating said switch machine to a normal position and to the reverse position respectively when energized by current of one polarity or the other, a locking relay deenergized when it is unsafe to operate said track switch and having front contacts included in said polar control circuit, whereby said switch machine cannot be operated to either position unless said locking relay is ener gized, a signal for governing trafiic over one of said routes, a circuit for clearing said signal including back contacts of said locking relay closed only if said locking relay is deenergized, and a lever which if moved to a particular position permits clearing of said signal and breaks the energizing circuit for said locking relay.

38. In combination, a track layoutincluding a track switch for establishing any one of a plurality of routes, a switch machine for controlling said track switch, a polar control circuit for operating said switch machine to a normal position and to the reverse position respectively when energized by current of one polarity or the other, a locking relay controlled in accordance with track occupancy and the direction of train movement and having front contacts included in said polar control circuit, whereby said switch machine can not be operated to either position unless said locking relay is energized, a signal for governing traffic over one of said routes, a circuit for clearing said signal including back ocntacts of said locking relay closed only if said locking relay is deenergized, and contacts which if moved to a particular position permits clearing of said signal and breaks the energizing circuit for said looking relay.

39. In combination, a track switch, a switch machine for operating said track switch, a locking relay for preventing operation of said switch machine, a free and non-lockable lever for applying current to a control circuit for said switch machine which control circuit may be broken by said lever and by a contact of said locking relay, a signal for governing movement of traffic over said track switch, and control means for said signal permitting clearing of said signal only if said lever and switch machine assume corresponding positions but which does not require such correspondence between said lever and switch machine to maintain said signal clear.

40. In combination, a track switch, a switch machine for operating said track switch, a locking relay for preventing operation of said switch machine, a free and a non-lockable lever for applying current to a control circuit for said switch machine which control circuit may be broken by said lever and by a contact of said locking relay, a signal for governing movement of traffic over said track switch, a control circuitfor said looking relay including a contact opened upon the approach of a train and a contact opened upon the initiation of the clearing of said signal, and control means for said signal permitting clearing of said signal only if said lever and track switch assume corresponding positions but which does not require such correspondence between said lever and track switch to maintain said signal clear.

41. In combination, a track switch, a switch machine for operating said track switch, a locking relay for preventing operation of said switch machine, a lever for applying current to a control circuit for said switch machine which control circuit may be broken by said lever and by a contact of said locking relay, a signal for governing movement of trafiic over said track switch, control means for said signal permitting clearing of said signal only if said lever and switch machine assume corresponding positions but which does not require such correspondence between said lever and switch machine to maintain said signal clear, and a signal control circuit for said signal con trolled by said control means and closed only if said locking relay is deenergized.

42. In combination, a track switch, a switch machine for operating said track switch, looking relays for preventing operation of said switch machine, a signal for governing movement of traflic over said track switch, a lever for applying current to a control circuit for said switch machine which control circuit may be broken by said leverand by the operation of said locking relays upon passage of a train over said track switch and upon the initiation of the clearing of said signal, and control means for said signal permitting clearing of said signal only if said lever and track switch assume corresponding positions but which does not require such correspondence between said lever and track switch to maintain said signal clear, whereby a new route may be pre-conditioned during the occupancy of a prior conflicting route as soon as said prior route has been established by a proceed signal and said new route is automatically set up upon leaving of the train off of said first route.

43. In combination, a track switch, a switch machine for operating said track switch, looking relays for preventing operation of said switch machine when a signal governing traffic over said track switch is at proceed or a train is passing over said track switch, a free and non lockable lever for applying current to a control circuit for said switch machine which control circuit may only be broken by said lever and by the operation of said locking relays, a signal for governing trafiic over said track switch, control means for said signal permitting clearing of said signal only if said lever and track switch assume corresponding positions but which does not require such correspondence between said lever and track switch to maintain said signal clear, and a signal control circuit for said signal controlled by said control means and closed only if one of said locking relays is deenergized, whereby a new route may be pre-conditioned during the occupancy of a prior conflicting route as soon as said prior route has been established by a proceed signal and said new route is automatically set up upon leaving of the train off of said first route.

44. In combination, a track switch, a switch machine for operating said track switch, looking relays for preventing operation of said switch machine when a signal governing traflic over said track switch is at proceed or a train is passing over said track switch, a lever for applying current to a control circuit for said switch machine which control circuit may only be broken by said lever and by the operation of said locking relays, a signal for governing movement of traffic over said track switch, and control means for said signal permitting clearing of said signal only if said lever and switch machine assume corresponding positions and one of said locking relays is deenergized but which does not require such correspondence between said lever and switch machine to maintain said signal clear, whereby a new route may be pre-conditioned during the occupancy of a prior conflicting route as soon as said prior route has been established by a proceed signal and said new route is automatically set up upon leaving of the train off of said first route.

45. In combination, a track switch, a switch machine for operating said track switch, locking relays for preventing operation of said switch machine when a signal governing traffic over said track switch is at proceed or a train is passing over said track switch, a lever for applying current to a control circuit for said switch machine which control circuit may only be broken by said lever and by the operation of said locking relays, a signal for governing movement of traffic over said track switch, and control means for as said prior route has been established by a prosaid signal permitting clearing of said signal ceed signal and said new route is automatically only if said lever and track switch assume corset up upon leaving of the train oil of said first responding positions but which does not require route.

such correspondence between said lever and track switch to maintain said signal clear, where- EARL M. ALLEN.

by a new route may be pre-conditioned during CHARLES A. BROOKS.

5 1 1 the occupancy of a prior conflicting route as soon HOWARD A. THOMPSON.

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