US2171756A

US2171756A - Signaling system

Info

Publication number: US2171756A
Application number: US14863A
Authority: US
Inventors: Lloyd V Lewis
Original assignee: Union Switch and Signal Inc
Current assignee: Hitachi Rail STS USA Inc
Priority date: 1935-04-05
Filing date: 1935-04-05
Publication date: 1939-09-05
Anticipated expiration: 1956-09-05

Description

Sept. 5, 1939. L. v. LEWIS SIGNALING SYSTEM 2 Sheets-Sheet 1 Filed April 5, 1935 INVENTOR yd Vlewz's BY Q MWLQ HIS Llo

ATTORNEY P 5, 1939- L. v. LEWIS 2,171,756

SIGNALING SYSTEM Filed April 5, 1955 QSheets-Sheet 2 Fig. 2.

INVENTOR Lloyd KLewis, 65% 741% HIS ATTORNEY Patented Sept. 5, 1939 UNITED STATES rATENT OFFlCE SIGNALING SYSTEM Application April 5, 1935, Serial No. 14,863

14 Claims.

My invention relates to signaling systems for railroads, and more particularly, to systems in which control signals are transmitted from a sending station to a remote receiving station.

One object of my invention is the provision, in a system of this character, of means for storing a plurality of signals at the receiving station and for cancelling these one at a time when acted upon.

The specific object of the forms of my invention herein illustrated and described, is the provision of a system for indicating the routes to be taken by vehicles successively approaching a junction point for diverging routes, in which the route indications are registered in advance and in which each route indication is stored until the corresponding vehicle passes the junction point.

The apparatus of my invention is an improvement upon that disclosed in an application of Paul Abeloos, Serial No. 699,798, filed November 25, 1933, for Automatic selection station, and. is also an improvement upon that disclosed in an application of Ralph Mordin, Serial No. 85,544, filed June 16, 1936, for Remote control apparatus.

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

In the accompanying drawings, Fig. l illustrates a route indicating system embodying my invention in which the route indications are registered by means of a visual indicator provided for the guidance of a local operator or leverman, and in which the registered indications are released manually. Fig. 2 illustrates another form of my invention in which a track switch is operated automatically in accordance with the route indications, and in which the indications are released automatically as the vehicles successively pass over the switch.

Similar reference characters refer to similar parts in the two views.

Referring first to Fig. 1, the diagram at the top represents a stretch of track over which railway cars or trains move from point a to point h, and thence over the track switch W to point .1: or to point y, according to the position of the track switch. Switch W is controlled by an operator or leverman stationed in a nearby signal tower D, who is kept informed as to the routes to be taken by approaching trains by means of indication lamps contained in a track model V, the lamps being controlled through the medium of the relays shown in the drawings by the operation of keys or push buttons contained in a control panel U.

The control panel may be located in the dispatchers oflice, or at a station 0 adjacent point a, where it may be operated either by an operator stationed at that point or by the crews of passin trains, as desired. The apparatus at tower D 5 includes a plurality of indicators arranged in groups comprising pairs of lamps designated XE! and YE l, XE2 and YE2, etc, which are selectively controlled by the relays in response to repeated operation of the keys of the control panel U to indicate the routes to be taken by the successive trains. That is, a first operation of key KX or KY will light lamp XE! or YEI, of the first indicator, to indicate that the first train is to move to point a: or to point 1 respectively; a second operation will light lamp XE2 or YE2, of the second indicator to similarly indicate the route to be taken by the next following train, while a third operation will light lamp XE3 or YES of the last-indicator. As each train passes switch W, the corresponding route indication displayed by lamp XE! or XEZ of the first indicator is cancelled by the operator at tower D by momentarily operating a release key KD associated with track model V. When key KD is released, the indication stored in the second indicator is transferred to the first so that lamp XE! or YE! becomes lighted in accordance with the indication which was previously stored in the second indicator and the second indicator then releases. The indication stored in the third indicator thereupon is transferred to the second and the third indicator releases. The first and second indicators will now indicate the respective routes to be taken by the two trains remaining in the stretch a-h. The keys of the control panel U maynow be actuated again to operate the third indicator to register the route to be taken by a following train. The route indications are thus registered in sequence as the trains enter the stretch, and the stored indications move step-by step through the indicators of the track model in response to the repeated operation of key KD as the trains move through stretch ab and pass switch W.

Each pair of indication lamps is controlled by a pair of stick relays bearing corresponding references such as relays XI and Y! for the first indicator, and associated with each pair of indication relays is a transfer relay L having a corre- 50 sponding'number. Each transfer relay serves to prevent further operation of its indicator after an indication has been registered and is stored therein, and also serves to control the transfer of an indication from one indicator to the next 55 b Relay X3 picks up and closes its contact I, bridgare released, and can be picked preceding indicator when key KD is operated. The group of relays associated with track model V as herein illustrated are controlled by a polar-- ized relay P over line wires I and 8,v by means of the manually operable keys KX and KY, relay B being energized by current of one polarity or the other depending upon whether key KX or KY is: operated. In series with relay P in: the line circuit, but located adjacent the control panel U is an indication relay ER controlling: a lamp E. Lamp E is lighted whenever one of the control relays KX or KY is operated provided relay P responds to store the indication. When one lamp of each of the three indicators is lighted, no further storage of indications is possible, and the arrangement is such that additional operations of key KX or KY will be without effect and the control operator will be made aware of this fact by the failure of lamp E to become lighted.

In order to simplify the drawings, I have shown only the terminals of the source of energy for the various relays and lamps, which terminals I have designated by the references 13 and C to indicate respectively the supply and common return terminals of the source,

Assuming the apparatus is; in its normal; condition with no lamp lighted, all the relays will be deenergized as shown in the drawing, except the transfer relay L3 of the last indicator, which is normally energized. The pickup circuit forrelay L3. may be traced from terminal B, back contacts 4 of relays Y3 and X3, relay L3, back contact 3 of relay P to the other terminal C of the same source. Relay L31 also has a stick; cir-. cuit which is the same as; the circuit just traced except that it includes its front contact I instead of the back contact of relay P. It follows, there! fore, that relay L3 is energized only when the indication relays X3 and Y3 of the third indicator up only when relay P is released.

Assume now that a train destined for point 1L passes point a. and that the control operator momentarily closes key KX. RelaysP- and ER become energized overa circuit which may be traced from terminal B, front contact I of key back contact I of key KY, relay ER, lin e wire- I, relay P, front, contact 3 of relay L3, line wire 8, back contact 2 of key KY, front contact 2; of key KX to the other terminal C- of the source, whereupon relay ER picks up, closing its contactv I to light lamp E, and polarized relay P picks up. to close its front contacts I. and 4 and; to open contact 3, and also closes its polar contact 2; to the left, completing a circuit which maybe traced either from terminal B, over back contacts 4 of relays Y2 and X2, or from terminal B, overback,

contact 3 of relay L2, and thence over front contact 2 of relay L3, front contact I and left-hand polar contact 2 of relay 1?, relay X3 to terminal C.

ing the contacts. of relays L3 and P in the circuit just traced so that relay X3 when picked up will remain energized irrespective of the condition of relay P or of relay L3, and will not release until.

'relays L2 and X2 or Y2, are energized. When relay P picks up, the closing of its contact 4, bridges contact 3 of relay L3 in the line circuit so that relay-P when picked up will remain energized as long as key KX is closed, even though relay L3 releases. Relay X3, by opening its back contact 4, releases relay L3. Since the pickup-circuit for relay L3 includes back contact'31 of. relay P, it follows that even though relay X3 becomes: released while relay P is energized relay; X3; can

not again be picked up until after relay P has been released to pick up relay L3, the arrangement being such that relay X3 can be operated but once for each operation of relay P and that neither relay X3 nor Y3 can be operated unless both these relays are released and relay L3 is energized.

When relay X3 picks up, a circuit is closed from terminal B, back contact 4 of relay Y3, front contact 4 of relay X3, relay L2, back contacts 3 of relays X2 and Y2 to terminal C so that relay L2 pick up closing its contact I to complete a connection from its right-hand terminal to terminal C in multiple with back contacts 3 of relays X2 and Y2. When relay L2 picks up, a circuit for relay X2 will be closed which may be traced either from terminal B, back contacts 4 of relays XI and YI, or from terminal B, back contact 3 of relay LI, thence over front contacts 2 of relays L2 and X3, relay X2 to terminal C. Relay X2 upon picking up closes its contact I bridging contacts 2 of relays X3 and L2 in its pickup circuit so that it will remain energized irrespective of the condition of these relays. Since back contact 4 of relay X2 and back contact 3 of relay L2 are now both open, relay X3 releases, opening the circuit for relay L2 and if relay P is now released also closing the circuit for relay L3, When relay L2 releases and relay L3 picks up, the pickup circuit for relay X3 or Y3 may be closed by again operating relay P and it follows, therefore, that a second indication may be stored in relay X3 or Y3 of the last indicator as soon as an indication has been transferred to relay X2 or Y2 of the next preceding indicator.

When relay X2 picks up, a circuit for relay LI is, closed which is similar to the circuit for relay L2 already described and when relay LI picks up, the pickup circuit for relay XI is closed which may be traced from terminal B, contact I of key front contacts 2 of relays LI and X2, relay XI to terminal C. Relay XI upon picking up closes its contact I bridging contacts 2 of' relays LI and X2 in the circuit just traced so that relay XI will remain picked up irrespective of the condition of these relays and can be released only by the operation of key KD. Since back contact 4 of relay XI and back contact 3 of relay LI are now both open, relay X2 will release and open its front contact 4 so that relay LI will release. Relay LI upon releasing, closes its back contact 3 to again connect terminal B of the source to the circuits for relays, X2 and Y2 so that a stored indication may be transferred from the third indicator to, the second. However, it will be noted that as long as an indication is stored in the first indicator and relay X! or YI is energized, relay LI will remain deenergized so that the pickup circuit of relay X! or YI will remain openand the stored indication can not be interfered with. Each of the indication relays such as XI or YI controls a corresponding lamp such as XEI or YEI in the track model. The circuit for XEI may be traced from terminal B, over front contact 5 of relay XI, lamp XE I to terminal C, the circuits for the, remaining lamps, being similar, as is apparent from the drawing. It follows, therefore, that when key KX is operated under the conditions assumed, lamps XE3, XEZ and XEI will:

same manner by closing key KY. Thus, when key KY is closed, current of the opposite polarity is supplied to the line circuit and relay P is energized in the opposite direction to close its polar contact to the right. to complete the pickup circuit for relay Y3.

Assume now that a second train destined for point y passes point a, and that the control operator operates key KY. Relays P, Y3, L2 and Y2 will be successively energized but further progression will be blocked because relay Ll does not pick up. Lamp YEZ will therefore remain lighted to indicate the route for the second train. Assume now that a third train passes point a and that key KX or KY is again operated. Relays and X3, or Y3, will pick up, but relay L2 does not pick up, and lamp XE3 or YE3 will remain lighted to indicate the route for the third train. Relay L3 now does not pick up when relay P is released, and the line circuit is held open so that further operation of key KX or KY is without effect and lamp E does not become lighted when these keys are operated, as long as an indication is stored in the third indicator.

Assume now that the first of the three trains occupying the stretch a-b' passes the switch W and that the operator at station D presses key KD to release Xi and extinguish lamp XEl. Since relay Y2 is energized, the closing of back contact 5: of relay X! will cause relay L! to pick up, and when key KD is released, the pickup circuit for Yl will be closed to pick up that relay thereby transferring the route indication stored in the second indicator to the first indicator so that lamp YE! will become lighted. Relays L! and Yi now being energized, the stick circuit for relay Y2 of the next succeeding indicator is open so that relay Y2 releases and this in turn causes relay Li to release. If relay X3 or Y3 is picked up, the release of relay Y2 will cause relay L2 to pick up and when relay Ll releases, the closing of its back contact 3 will complete a circuit to transfer the indication stored in the third indicator to the second, and relay X3 or Y3 and then relay L2 will release, and relay L3 will pick up.

There are now two trains remaining in stretch a-b and their route indications are stored in the first and second indicators respectively, and the third indicator has become available for registering the route to be taken by a following train.

Assume now that key KD is operated as the first of these two trains passes switch W. The route indication stored in. the first indicator will I be cancelled, and when key KD is released, the

indication stored in the second indicator will be transferred to the first, as before. Another operation of key KD will cancel this indication and when key KD is restored, the apparatus will be i in its original condition.

T of relays extended to any desired length by merely inserting in the chain additional groups of relays each of which are similar to and are connected into the circuits in the same manner as the relays L2, X2 and Y2 of the second indicator. In practice, the number of indicators employed will generally be more than three, since it is desirable to provi e a number of indicators equal to the maximum number of trains that can occupy the stretch ab at any one time, and point a may be at a considerable distance from point b. Furthermore, each indicator may readily be modified to provide more than two indications by merely providing each indicator with additional X and Y relays, each indicator requiring but one L relay irrespective of the number of indication relays, and by providing a relay P or an equivalent remote control means for each pair of indications. When arranged to provide additional indications the apparatus of my invention is particularly adapted for use as an annunciato-r of the approach of trains to a large railway terminal station, to facilitate the switching of the trains to the proper terrmnal tracks, and when so employed the number of different indications controlled by each indicator will, in general, be equal to the number of terminal tracks in the station.

Referring now to Fig. 2, the polarized relay P and the three groups of relays X, Y and L function in precisely the same manner as in Fig. l, but relays Xi and Yi of the first indicator automatically control the operation of a power switch machine SM for operating the track switch W, and no operator is needed at point a. The usual detector track circuit T having a track relay TB is provided for the track section containing the switch and the switch machine is provided with the usual polarized control relay WR having a circuit including a front contact 2 of the track relay so that the switch can not be operated when a train is occupying the detector section. The local circuits for the switch machine have been omitted as these are well known in the art and form no part of the present invention, but they may be arranged, for example, as shown in the Willard Patent No. 1,380,452, issued June 7, 1921. The switch control relay WR is controlled by the relays of the first indicator in such a manner that if the section T is unoccupied, the switch will be operated to normal when relay Xi is energized to permit a train movement from point 27 to point .r and will be reversed when relay Y! is energized to permit a train movement from point b to point y. In Fig. 2, the release key KD of Fig. 1 has been replaced by a front contact l of track relay TR, so that the indication stored by relay XI or Yl is released automatically as soon as the train enters section T to pass over the switch and relay X5 or Y! is again rendered available to register the route to be taken by a following train as soon as the first train passes out of the switch section. Relays XI and Yi control indication lamps X1515 and YEl, as in Fig. 1, and associated with these lamps is a pair of manually operable keys KXl and KY! by means of which the train crew of an approaching train may operate the switch to change the route if they so desire, as would be the case, for example, if an error has been made in setting up the route.

The pickup circuits for relays Xi and Yl, in Fig. 2, include the front contact of track relay AR of an approach section A adjacent sec tion '1', and a signal S is provided at the entrance to section A. It is to be understood that signal S is controlled automatically in the usual manner to indicate the position of switch W, and that signal S indicates stop when section A or section T is occupied. The arrangement is such that the switch can not be operated by remote control after a train has passed the signal and occupies section A or section T.

Assuming that the indicators have been operated as already described in connection with Fig. 1, up to the point where relays X2 and Li have become energized, if sections A and T are unoccupied, the pickup circuit of relay XI will be closed, which may be traced from terminal B, front contacts I of relays TR and AR, front contacts 2 of relays X2 and LI, relay XI to terminal C. When relay XI picks up, its stick circuit becomes closed, which circuit may be treated from terminal B, front contact I of relay TR, back contact 6 of relay YI, front contact I and winding of relay XI to terminal 0. Lamp XEI now becomes lighted, relays X2 and LI release in sequence, and the normal circuit for relay WR becomes closed. This circuit may be traced from terminal B, front contacts 2 of relays XI and TR, relay WR, back contact 2 of relay YI to terminal C, so that relay WR becomes energized in the normal direction, as shown in the drawings, and energizes the switch machine SM to operate sun'tch W to normal. The pickup circuit by which relay YI is controlled by relay Y2 is similar to the pickup circuit of XI but includes front contact 4 of relay LI, and relay YI has a stick circuit similar to that of relay XI and when energized closes the reverse circuit of relay WR to cause switch W to be reversed, as is apparent from the drawings.

Assuming now that the approaching train occupies section A but not section T, and that the train crew operate key KYI. Relays AR and LI now being deenergized, an auxiliary pickup circuit for relay YI will be closed which may be traced from terminal B, front contact I of relay TR, back contact I of relay AR, key KY1, back contact 4 of relay LI, relay YI to terminal C, so that relay YI picks up, opening its back contact 6 in the stick circuit of relay XI. Relay XI therefore releases and by closing its back contacts 6 and 2 establishes the stick circuit for relay YI, and completes the reverse circuit for relay WR, so that the switch will be operated to reverse. Relay X! may similarly be picked up by closing key KXI to operate the switch to normal, as is apparent from the drawings.

When the train passes over the switch the pickup and stick circuits of relays XI and YI are opened by contact I of relay TR, and if a route indication is stored in the second indicator. relay LI will pick up as soon as relay XI or YI releases, and as soon as the train leaves section T the closing of contact I of relay TR will cause the transfer of the route indication to the first indicator, and relay WR will become energized to operate switch machine SM as already described, so as to set up the route for the next train.

The apparatus at the control station 0 is also arranged differently in Fig. 2, in order to provide an arrangement which insures positively that but one route indication will be registered for each train. To accomplish this result, a short track section CA is provided adjacent point a, having a track relay OAR which must be released to render key KX or KY operative, and these relays are each provided with a relay XR or YR. In Fig. 2, relay P is energized in series with relay XR when key KX is operated, and in series with relay YR when key KY is operated, provided relay L3 is energized and a train is occupying section OA. Relays XR and YR are stick relays and remain energized to hold the line circuit closed until the train moves out of section OA, and until this occurs render the circuits controlled by keys KX and KY non-responsive to further operation of these keys.

Assuming that key KX in. Fig. 2 is closed, and that section 0A is occupied, the normal circuit for relay P will be completed and may be traced from terminal B, back contact 2 of track relay OAR, key KX, relay XR, back contact 2 of relay YR, line wire I, relay P, front contact 3 of relay L3, line wire 8 to the other terminal C of the source. When relay XR picks up it closes its contact I bridging key KX so the circuit will remain closed until track relay OAR picks up, since, as in Fig. 1, when relay P picks up, it closes its front contact 4 to maintain the line circuit closed after relay L3 releases. The reverse circuit for relay P is similar but includes key KY and relay YR and receives energy over back contact I of relay OAR from a terminal N which is connected to terminal C through a source of energy of the opposite polarity to that connected betwen terminals B and C. Lamp E, which functions in the same manner as in Fig. 1, becomes lighted when either relay XR or YR is energized to close its front contact 3, as is apparent from the drawings.

The control apparatus at station 0 in Fig. 2 is wholly interchangeable with that of Fig. 1, and may be used to control the track model of Fig. 1. Likewise the indications of the track model may be cancelled by the movement of trains past point D in Fig. 1 in the same way as in Fig. 2, as is obvious.

The apparatus of Fig. 2 is adapted not only to the control of main line train movements, but is equally suited to control the switching of cars in classification yards, where it is the practice to assign a particular route to each car as it passes a control point and then to operate one or more switches to direct the car to the desired terminal track.

Although I have herein shown and described only two forms of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In a signaling system, a series of indication relays, control means for at times energizing the last relay of said series, a series of transfer relays including one for each remaining relay of said series, a pickup circuit for each transfer relay including a back contact of the associated indication relay and a front contact of the next succeeding indication relay of the series, a stick circuit for each transfer relay including its own front contact and a front contact of said succeeding indication relay, a pickup circuit for each indication relay except the last including front contacts of the associated transfer relay and of the next succeeding indication relay of the series, a stick circuit for each indication relay except the first including its own front contact and, in multiple, back contacts of the next preceding indication relay of the series and of the transfer relay associated therewith, a release contact, a stick circuit for the first indication relay of the series including its own front contact and said release contact, and indication means controlled by said first indication relay.

2. In a signaling system, a series of indication relays, a series of transfer relays including one for each indication relay, a control relay, a pickup circuit for the last transfer relay of said series including back contacts of the control relay and of the last indication relay, a stick circuit for said transfer relay including its own front contact and the back contact of the last indication relay, a pickup circuit for the last indication relay including front contacts of the control relay and of the last transfer relay, a pickup circuit for each remaining transfer relay including a back contact of the associated indication relay and a front contact of the next succeeding indication relay of the series, a stick circuit for each said remaining transfer relay including its own front contact and a front contact of said succeeding indication relay, a pickup circuit for each indication relay except the last including front contacts of the associated transfer relay and of the next succeeding indication relay of the series, a stick circuit for each indication relay except the first of the series including its own front contact and, in multiple, back contacts of the next preceding indication relay of the series and of the transfer relay associated therewith, a release contact, a stick circuit for the first indication relay of the series including its own front contact and said release contact, and indication means controlled by said first indication relay.

3. In a signaling system, a series of indication relays, control means effective when operated for at times energizing the last relay of said series, a series of transfer relays including one for each remaining relay of said series, an energizing circuit for each transfer relay closed only when the associated indication relay is released and the next succeeding indication relay of the series is energized, an energizing circuit for each indication relay except the last closed only when its transfer relay and the next succeeding indication relay of the series are energized, means rendered effective when an indication relay and its transfer relay are both energized for releasing in sequence the succeeding indication relay and said transfer relay, means preventing the reenergizaticn of the last indication relay until the control means is again operated, means independent of said relays for releasing the first indication relay of the series, and indication means controlled by said first relay.

4. In a signaling system, a series of relay groups each including a plurality of indication relays, a series of transfer relays including one for each group except the last, a pickup circuit for each transfer relay closed when all the indication relays of its group are released and an indication relay of the next succeeding group is energized, a stick circuit for each transfer relay effective to maintain it energized until such energized indication relay is released, means for energizing a selected indication relay of the last group, means effective when each transfer relay is energized to energize that indication relay of its group which corresponds to the energized indication relay of the next succeeding group, a stick circuit for each indication relay for maintaining it energized until released, means effective when an indication relay and the transfer relay for the same group are both energized to release the energized indication relay of the next succeeding group, means for releasing the energized indication relay of the first group.

5. In a signaling system, a series of indicators each adapted when operated to store a selected indication, a series of transfer relays including one for each indicator except the last of the series, a pickup circuit for each transfer relay closed only when the corresponding indicator is released and the next succeeding indicator is operated, a stick circuit for each transfer relay which becomes effective when it picks up to hold it energized until the next succeeding indicator is released, means for operating the last indicator of the series, means effective when each transfer relay is energized to transfer to its indicator the indication of the next succeeding indicator of the series, means effective when any indicator except the last is operated to release the next succeeding indicator of the series, and means for releasing the first indicator of the series.

6. In a signaling system, a series of indicators, each adapted when operated to store a selected indication, a series of transfer relays, including one for each indicator, a pickup circuit for each transfer relay except the last of the series closed only when the corresponding indicator is released and the next succeeding indicator is operated, a stick circuit for each transfer relay except the last which becomes effective when it picks up to hold it energized until the next succeeding indicator is released, control means for operating the last indicator effective only when the last transfer relay is energized, a pickup circuit for the last transfer relay closed only when the control means and the last indicator are both released, a stick circuit for the last transfer relay which becomes effective when it picks up to hold it energized until the last indicator is operated by said control means, means effective when each remaining transfer relay is operated to transfer to its indicator the indication of the next succeeding indicator of the series, means effective when any indicator except the last is operated to release the next succeeding indicator of the series, and

' means for releasing the first indicator of the series.

7. In combination with a stretch of railway track, a track circuit at one end of the stretch having a track relay, a track switch at the other end of the stretch, a route indicator adjacent the switch for indicating the routes to be taken by trains which have passed over said track circuit and are approaching the switch, manually operable contacts and a stick relay adjacent said track relay, a line circuit including said manually operable contacts and said stick relay and extending to the other end of the stretch, means responsive to the closing of said line circuit to ope erate said route indicator and said stick relay, means preventing the closing of said line circuit except when the track relay is released, and

' means controlled by the stick relay when energized to maintain the line circuit closed as long as the track relay remains deenergized irrespective of further operation of said manually operable contacts.

8. In combination with a stretch of railway track, a track circuit at one end of the stretch having a track relay, a track switch at the other end of the stretch, a route indicator adjacent the switch for indicating the routes to be taken by trains which have passed over said track circuit and are approaching the switch, manually operable contacts and a stick relay adjacent said track relay, a line circuit including said manually operable contacts and said stick relay and extending to the other end of the stretch, means responsive to the closing of said line circuit to operate said route indicator and said stick relay, means preventing the closing of said line circuit except when the track relay is released, means controlled by the stick relay when energized to maintain the line circuit closed as long as the track relay remains deenergized, and a visual indicator controlled by the stick relay and indicating when the line circuit is closed.

9. In combination with a railway track switch,

a normal control relay and a reverse control relay for controlling the switch, a stick relay, remotely controlled means effective only when said control relays are both deenergized to pick up said stick relay, means effective when said stick relay is energized to energize a selected one of said control relays in accordance with the condition of said remotely controlled means and to then release said stick relay, means controlled by the selected control relay to operate the track switch, and means responsive to the movement of a train over the switch to release the selected control relay.

10. In a signaling system, a series of normally deenergized indicators, each adapted when energized to store a selected one of a plurality of different indications, control means for selectively energizing the last indicator of the series to store a selected indication therein, said control means beng manually operable only when one or more of said indicators are normal, transfer means for each indicator except the first of the series for transferring the indication stored therein to the next preceding indicator of the series, each said transfer means being effective only when such preceding indicator is normal, means controlled by each transfer means for restoring the associated indicator to normal when the next preceding indicator becomes energized, means effective upon restoration of the last indicator to normal for preventing further operation of said indicators until after said control means has been manually restored to normal, and means for restoring the first indicator of the series to normal.

11. In combination, a detector section of railway track including a track switch, an approach section adjacent said detector section, a power switch machine for operating the switch, a series of indicators each comprising relay means adapted to be energized in a particular arrangement for each position of the track switch, manually operable means for energizing the last indicator of the series to register a control for'the track switch, transfer means. associated with each indicator except the last of the series and responsive to the release of such indicator to automatically energize it in accordance with the condition of energization of the next succeeding indicator of the series and to then release such succeeding indicator, means preventing the energization of the first indicator of the series except when said detector section and approach section are both unoccupied, means for controlling the switch machine in accordance with the condition of energization of said first indicator, and means for releasing said first indicator when th detector section becomes occupied.

12. In combination, a detector section of rail- Way track including a track switch, an approach section adjacent said detector section, a power switch machine for operating the switch, relay means adapted to be energized in a particular arrangement for each position of the track switch, manually operable remote control means for energizing said relay means to register a control for the track switch, means preventing the energization of said relay means by said remote control means except when the detector section and approach section are both unoccupied, manually operable means adjacent the track switch for energizing said relay means when the approach section is occupied and the detector section is unoccupied, means for controlling the switch machine in accordance with the condition of energization of said relay means, and means for releasing said relay means when the detector section becomes occupied.

13. In combination, a detector section of railway track including a track switch, an approach section adjacent said detector section, a power switch machine for operating the switch, relay means adapted to be energized in a particular arrangement for each position of the track switch, manually operable remote control means for energizing said relay means to register a control for the track switch, means preventing the energization of said relay means by said remote control means except when the detector section and approach section are both unoccupied, manually operable means adjacent the track switch effective only when the approach section is occupied to change the condition of energization of said relay means, means for controlling the switch machine in accordance with the condition of energization of said relay means, and means for releasing said relay means when the detector section becomes occupied.

In a signaling system, a series of indication reays, a series of transfer relays including one for each indication relay except the last of the series, a pickup circuit for each transfer relay closed only when the corresponding indication relay is released, a stick circuit for each transfer relay which becomes effective when it picks up to hold it energized until the next succeeding indication relay is released, means for energizing the last indication relay of the series, means effective when each transfer relay is energized to energize the corresponding indication relay provided the next succeeding relay of the series is energized, means effective when any indication relay except the last becomes energized to release the next succeeding indication relay of the series, and means for releasing the first indication relay of the series.

LLOYD V. LEWIS.