US2084302A - Train describer system - Google Patents

Description

June 15, 1937. s. N. WIGHT TRAIN DESCRIBER SYSTEM 3 Sheets-Sheet 1 Filed Oct. 15, 1936 an E 1. l|l|.|l||| E m UQ St:

INVENTOR BY 5.7L. 209% M. M ATTORNEY S. N. WIGHT TRAIN DESGRIBER SYSTEM Filed Oct. 15

June 15, 1937.

, 1936 3 Sheets-Sheet 2 INVENTO M ATTORNEY June 15, 1937.

S. N. WIGHT TRAIN DESCRIBER SYSTEM 5 Sheets-Shet 5 Filed Oct. 15, 1936 INVENTOR BY 2 ATTORNEY,

Patented June 15, 1937 UNITED .STATES TRAIN DESCRIBER SYSTEM Sedgwick N. Wight, Rochester, N. Y., assignor to General Railway Signal Company, Rochester, N. Y.

Application October 15,

9 Claims.

This invention relates to centralized traffic controlling systems for railroads and it more particularly pertains to the identification of trains in the so-called entrance-exit or NX type of interlocking system.

The present invention relates to the application of a train describer system in a system of the entrance-exit route type interlocking system, disclosed in my prior application Ser. No. 69,905 filed March 20, 1936.

The organization of an entrance-exit or NX type system to which the train describer feature of the present invention is applied, contemplates a miniature track diagram associated with an interlocking plant, which track diagram corresponds to the actual track layout in the field. This track diagram has initiating or entrance buttons at each of the route determining points and completion or exit buttons for each of the points to which traflic may go. In other words, for each signal location there is an entrance button, which button requires the cooperation of an exit button for the end of a proposed route in order to establish movement'of traflic in a particular direction over a particular trackroute.

In accordance with the present invention a plurality of auxiliary buttons are associated with certain of the exit buttons, which when actuated complete the setting up of the route in the same way as the regular exit button, and, in addition, condition circuits for transmitting indications relating to the classes of trains traversing the route.

An important feature of the present invention relates to the cooperation of the circuits controlled by the entrance-exit buttons with the auxiliary buttons in such a way that a single manual operation for the completion of each route is effective to not only complete the desired route, but also transmits indications relating to the destination or identification of trains traversing the route.

Other objects, purposes and characteristic features of the present invention will be in part obvious from the accompanying drawings and in part pointed out as the description thereof progresses.

In describing the invention in detail, reference will be made to the accompanying drawings, in which like reference characters designate the same parts in the several views' and in which like letters in the reference characters designate similar functions and in which like preceding numerals associated with the reference characters, when applied to different letter 1936, Serial No. 105,733

characters, represent the inclusion of such device withina particular group; and in which:-

Fig. 1 illustrates the layout of a system including a track diagram and the associated track layout in an interlocking plant, in which one route leads to a'distant location at which the train describer or train classindicator is located. 1

Figs. 2A and 2B (with Fig. 2A placed above Fig. 2B) illustrate the detailed circuit arrange-' ment for setting up routes in the entrance-exit type system to which the present invention is applicable, and furthermore indicate the control of the train describer. lamps at the distant location. a I

Fig. 3 shows a modification of' the control of the train describer apparatus.

For the purpose of simplifying the illustrations and facilitating in the explanation, various parts and circuits constituting the embodiment of the invention have been shown diagrammatically and certain conventional illustrations have been employed. The various relays and their contacts are illustrated in a'conventional manner, with symbols employed to indicate connections to the terminals of batteries or other suitable sources of current, instead of showing all of the wiring connections to such terminals.

Certain contacts of exit buttons 3XBA and 3XBB are shown in Fig. 2B, the dotted lines con- Track layout of Fig. 1.In the accompanying v drawings, the invention has been shown applied to a track layout including a stretch of double track connected by a cross-over having switches TSa and T80. For convenience the cross-over has been indicated as operated by a single switch machine ISM (see Fig. 2A), although two such switch machines may be used and they may be of any suitable type, such, for example, as disclosed in the patent to W. K. Howe No. 1,466,903 dated September 4, 1923. It will be understood that the invention is not limited to the particular layout disclosed, since it may be applied to any track layout found in practice.

The track layout includes a main line track having rails 6 which are divided into track circuits by the usual insulated joints and including the usual track battery and a track relay 6T.

Another main line track includes track rails I which are likewise divided into track circuits by the usual insulated joints and has the usual track battery and a track relay 7T. The'crossover is the other or both of the track relays will" be deenergized when the cross-over is occupied.

Signal 28 provides means for governing eastbound traffic over the rails I, while signal 38 provides for governing west-bound traffic' over rails l as well as over the cross-over. Signal 48 pro vides means for governing east-bound traflic over rails 6 and over the cross-ovenwhile signal 58 provides for governing west-bound traific over rails 6; Although signals 3S and. 4.8 are shown as governing both main line and cross-over traflic,

it is to be understood that separate signals may be employed if desired. 7

The track, including rails I, is illustrated as extending to adistant point, at which the train class indicator is located and in the following-description it will be assumed, as a typical example, that trains traversing a'route over the lower track railsl, completed bytheoperation of exit button 3X13, will not be indicated on the train class indicator. Trains traversing this 'routewhen completed by the operation of button 3XBAwillbe announced at the distant point by the actuation of the indicator lamp AL. Trains traversing this route when completed by the actuation of buttons 3XBB will be indicated at the distant point by the actuation of lamp EL. 7 The 'cross-over illustrated in Fig. 2A and the switch machine lSl/i,;whijch-controls the switches of this cross-over, preferably have associated therewith a point detector contact mechanism, such as shown, forexample, in the patent to C. S. Bushnell No. 1,517,236, dated November 25; 1924. The contacts of this mechanism (not shown) are provided to control a switch position indicating relay. WP of the usual polar neutral type, so that relay WP is energized with one polarity orthe other for positioning its polar contacts to one position or the other when the track switch is in normal or reverse locked positionsin correspondence with switch machine lSM. Relay WP is deenergized whenever the cross-over. track switches are unlocked or in operation either by the switch machine ISM or by hand. 7

Control panel of Fig. -1.-In the central ofiice a I control machine includes a control panel provided with suitable control buttons and indicators, including entrance buttons ZNB, 3NB, VB and BNB, which buttons are in positions corresponding to their respective signals, as indicated-by the "preceding numeralsQ Located at the center of that when an entrance button is rotated its corresponding repeating relay is picked up.

The exit buttons XB are of the self-restoring push button type and have arrows located thereon which indicate the direction of trafiic which they govern. The actuation of an exit button closes Since the control of these indicators is immaterial to anunderstanding of the present invention, it is only necessary to know contacts for completing the circuits for route relays shown specifically in Fig. 2A.

Thecondition of track occupancy is indicated on the control panel by indicators BTK and 'ITK,

which are suitably controlled by their correspond,-

ing track relays (ET and IT of Fig. 2A), all of which has been omitted from the present disclosure for the sake of simplicity.

Above the portion of the miniature track diagram representative of the cross over, is located a switch control lever ISML and a correspondence lamp or indicator IGOR. Ihe switch contol lever and the correspondence indicator are used more particularly under emergency conditions and may be placed at some other location if desired.

Miniature switch points to associated with the upper and lower. track diagram are provided for indicating the positions of the associated track switches and are underthe control of suitable correspondence circuits which are not shown, since this feature of the system is not related in any way to the present invention. 7

Control circuits Figs. 2A and 2B.Associate with the entrance and exit buttons NE and X3 respectively, are suitable route relays of the polar neutral type such as relays 4-5, 43 and 2-3. These'route relays are controlled in a manner more specifically pointed out later in thespecification and also described in detail in myabo'vementioned application Ser. No. 69,905, foreffecting the control of the cross-over through the medium of a switch control relay Z of the polar neutral type and a lock repeating relay LP of the neutral slow releasing type, which relays are assumed to be located in theoffice or tower.

The control of the track switch is transmitted over a line wire 26 and a common return wire 21, to which the switch control relay WZ is connected, for' locally controlly switch machine ISM. A look relay L is provided at the field station and is controlled through a signal at stop relay M and track relays GT and IT, as well as by means of suitableapproach locking indicated by jumper AP, it be ing understood thatv the usual approach and release locking may be inserted where this jumper is indicatedwithout departing from the scope of the present invention.

, Although the switch position repeating relay WP is usually located at the field station anda repeater is provided in the control ofilce, for the sake of simplicity only the WP relay located in the control office is shown, since suitable control may be provided to accomplish the operation of the WP relay in the ofiice in any desired manner. .Since it is assumed that the train describer feature of the present invention isoperable by completing the setting up of a route by the operationof an exit button, two auxiliary exit buttons 3XBA and, 3XBB have been provided for complet-.

ing such a route and for transmittingthe train identification to the remote point; Train identi-' fication relays AS and BS are operated i'n'respons'e to'the actuation of exit buttons 3XBA and 3XBB respectively for lighting train identification lamps ALand BL, respectively. Atrainidentification lamp remains lighted, when once lighted, until the operator at the distant location operates an associated. cancelling'button AP for lamp AL or BP for lamp BL. v

In the Fig. 3 modification, buttons AP and BF correspond to buttons AP and BP respectively, of Fig, 2B. Lamps AL and BL correspond to lamps AL and BL of Fig. 2B, track relay 1T corv responds to relays IT of Fig. 2A. Slow acting relays AK and BKare picked up by the actuation of exit buttons SXBA and 3XBB which but-' tons correspond to buttons 3XBA and 3XBB, respectively, of Fig. 2A. I Relays AK and BK control the operation of relays AS and BS the latter corresponding to relays AS and BS of Fig. 2B.-

The operation of Fig. 3 differs from the-operation disclosed in Figs. 2A and 2B, in that the actuation of a train indicator exit button is store-d by the picking up of the associated slow acting relay (AK or BK). Then the lamp control relay is picked up for lighting the lamp when the track circuit is occupied, after which the lighted lamp is extinguished by the operation of the associated cancelling button. The-purpose of Fig. 3 modification is to permitthe operator to cancel a train identification in the event that a wrong exit button'is operated. This cancellation can be effected any time up to the occupancy of the track section by a train and the consequent picking up of the AS or BS relay by the dropping of one or the other of the track relays.

Although the present invention is only disclosed for identifying two different types of trains, A trains or B trains, it will be apparent that provision can be made for identifying any desired number of'trains by increasing the number of auxiliary exit buttons associated with the button which completes the setting up of the route over which the identified trains are to pass.

It is believed that the characteristic features of the present invention will be best understood by further description being given from the standpoint of operation.

Operation Setting-up a Toute.It will be assumed that the operator desires to set up a route over the cross-over from signal as to signal 38 and on through the interlocking plant, with no train identification being effected. To do this, he rotates entrance button 4N3 in a clock-wise direction until the pointer on this button agrees with the position of the arrow on signal indicator @SK. Then knowing that no route is set up over the cross-over (because the route indicators are not illuminated) he actuates exit button 3X5.

The actuation of entrance button lNB picks up relay 4R (see Fig. 2A) and with button 3X3 actuated, a circuit is closed for route relay l-3, extending from front contact Bit of relay QR, back-contact 3! of relay 6-5, winding of relay 43, back contact '32 of relay 2-3, back contact 33 of relay SR, and contact 34 of exit button 3XB to The current flowing in this circuit actuates the polar contacts of relay d3 to the right and picks up the neutral contacts for completing a stick circuit for re1ay" l3, which circuit includes front contact 35 of relay i.3 and polar contact 36 of relay 4-3 in a right-hand position, this circuit being independent of contact 34 of button 3XB, which contact is only momentarily closed, since the button is of the selfrestoring type.

The energization of relay l3 opens the pickup circuit of relay l5 at back contact El and the pick-up circuit for relay 2-3 at back contact 38, for the purpose of interlocking these relays so that no conflicting route can be set up.

Relay Q3 closes an energizing circuit for relay Z extending from front contact 40 of relay 4-3, lower winding of relay Z, and back contact 4| of relay Z to The currentflowing in this circuit causes the polar contactspf relay Z to be actuated to the left and the neutral contacts to be picked up. Since the polar contacts of such a relay respond before the neutral contacts, polar contact 42 applies in its lefthand dotted position to the lower winding of reclosure of front contact 53 of relay 2-3 or con- I tact '44 of lever lSML in its lower dotted line position applies to the left-hand terminal of the upper winding of relay Z, but this is ineffective to energize the relay because of open back contact as and because contact 32 is not closed in its right-hand position.

The actuation of the polar contacts of relay Z to the left closes a circuit from the negative terinal of battery B, contact 36 of relay 2. in its left-hand dotted position, through the upper winding of relay LP, front contact ll of relay LP, contact 48 of relay WP in its right-hand position, line conductor 25, front contact ll-9 of relay L and winding of relay WZ to the mid-tap of battery 13 over return conductor 2l. Current flowing in this circuit causes the polar contacts of relay WZ to be actuated to the left for applying through front contact iii of relay WZ, polar contact 55 of relay WZ in its left-hand dotted position, to the reverse operating circuit for switch machine 18M, which causes switch machine 18M to actuate the cross-over track switches to re verse locked positions.

The operation of the cross-over track switches to reverse positions causes the operation of the polar contacts of relay WP to left-hand positions, followed by the picking up of the neutral contacts or" this relay. A circuit is now closed for clearing signal is extending from front contact 55 of relay WP, polar contact 5? of relay WP in a left-hand clotted position, front conj,

tact '58 of relay 2-3, contact 559 of relay l3 in its right-hand position, conductor 6i] and through the various selections necessary to clear signals is, as indicated by the dotted line.

The clearing of signal as causes the deenergization of relay M which, by means of open front contact 18, effects the deenergization of relay L. A stick circuit is now closed for relay WZ extending from the terminal of field battery FB, contact SI of relay WZ in its left-. hand dotted position, front contact 62 of relay WZ, back contact 49 of relay L and winding of relay WZ to the mid-tap of battery FB. This circuit maintains relay WZ energized even though its control from the central oflice is prevented.

The opening of front contact '49 deenergizesrelay LP and therefore as soon as signal as goes to stop and such condition is indicated to the operator by signal indicator lSK, he can return the entrance button 4NB to normal, which deenergizes relays 4R, 4-3 and Z. However, relay LP remains deenergized because relay'L does not pick up and close front contact 49 until the train has passed beyond both track sections 6 and l.

The occupancy of track sections 6 and l is indicated to the operator by indicators STK and lTK controlled by relays ST and "ET, although such control has not been shown. Furthermore,

the miniature switch points is and indicator QSK indicate to the operator what route is being set up and when it has reached'a locked condition. Lock lamps arealso provided (not shown), which entrance-exit buttons accomplishes the energicorrespond to the associated switch points illustrated in Fig. 2A. The control of these look lamps is not material to an understanding of the present invention, but it will be understood that they are, illuminated whenever the crossover is locked'against' operation or is being controlled to a new position.

As soon as the train passes beyond section 1 and lock relay L is energized, lock repeater relay LP is picked up for restoring the control of switch control relay WZ to the circuit including polar contacts 45 and 66 of relay Z, this latter relay being deene'rgized upon the restoration of entrance button ANB to its normal position because of open front contact 4B of relay 4-3.

The provision of relay LP in the circuit including its front contact 41, cooperating with contact 48 of relay WP, is for the purpose of providing the electric lock equivalent feature and requires correspondence between the positions of the polar contacts of relay Z and the polar contacts of relay WP in order for relay LP to be energized. The function of this electric lock equivalent feature'will not be explained in detail, since this feature has been disclosed in my prior application Ser. No. 69,905. 7

It isbelieved that it will be readily understood by analogy to the above description, how a route can be cleared from signal As to signal 5S, or in the reverse direction, or how various other similar routes can be set up. I The operation of the zation of one or the route relays 4-5, 4-3 or 2-3 with one polarity or the other depending upon the particular route and direction in such route'to be established. Since the train identi- The closure of contact 44 in its lower dotted line position energizes the upper winding of relay Z, and since the two windings ofrelay Z are wound in opposite directions the energization .of its upper winding actuates its polar contacts to the right, in the same manner that the closure of front contact 65 of relay 4-5 or front contact &3 of relay 2-3, which relays are energized for setting up routes 4-5 and 2-3, respectively. It

that the operation of lever ISML is apparent theposition determined to aposition contrary to by a particular route relay already picked up,

will not cause the energization of the relay Z in the opposite direction, because both; neutral contacts 4! and 45 are open and because polar contact 42 is not in position for allowing such opposite energization.

A correspondence indication is providedfor the purpose of indicating whether or not the switch control relay Z is in correspondence with the track switch under such conditions as require the operation of lever lSML. This correspondence indicator ICOR is energized when the track switch is unlocked, as indicated by the deenergization of relay WP and the consequent closure of back contact 1.0. When relay Z is out of correspondence with the locked position of 1 signal 33. a he Wishes tov announce that thetrain is of a particular class, for example, an A' class train the track switch, as indicated-by relay WP, a circuit is closed for indicator ICOR extending L from front contact 10 of relay WP, polar contact I I of relay WP in'a normal position, p olar contact 12 of relay Z in a reverse position and indicator [COR to Similarly, this circuit is completed with relay WP having its contact H in a reverse position and relay Z having its contact'lZ in a normal position.

Although the detailed circuits effective for i clearing routes otherv than those above described will not be pointed out, it is believed desirable to point out the control of the route relays under such conditions.

Assuming thatroute relay 4-5 is picked up to establish a route over the .main track 6 either from signal 4S to signal 58, or inthe reverse direction, then relay Z is energized to its normalposition by reason of the closure of front con-, tact E5 of relay 45.

If route relay 2-3 is picked up to establish a. route over the main track I either from signal 26 to signal 38, or in the opposite direction, then relay Z is energized to a normal position by reason of the closure of front contact 43 of relay 2-3.

Train identification-It has been explained in detail how the operator-completes a route for a train (identification not'effecte'd), from signal is to signal 3S by operating completion button SXB. It will now be assumed that he wishes to complete a route either from signal 4Sor 2Sgto In this case it willbe assumed that and consequently instead ofoperating completion button 3X3 he will operate completion button 3XBA.

The operation of button 3XBA effects the set-.

ting up of the route by way of the lower track section in exactly the same manner as described in connection with the operation of button 3X3, since contacts 14 of button 3XBA are in multiple with contacts 34 ofbutton 3X3." The operation of button 3XBA furthermore closes a circuit for picking up relay AS which extends from contact 20 of button 3XBA and winding of relay AS'to The operation of relay AS closes a stick circuit for itself extending from normally closed contact 61 of cancelling button AP, front contact 2 I and winding of relay AS to The picking up of relay AS closes an obvious circuit at front contact 22 for,lightingiamp AL, which gives an indication of the class of the train approaching the remote point.- Relay AS then remains in its energized condition until the operator at the remote point acuates button AP, for deenergizing relay AS and extinguishing lamp AL.

In the event that this is a class B train, then button 3XBB is actuated to complete the NX route in the same manner as'if he had used completion button 3XB, because contact 84 of button 3XBB is in multiple with contact 34 of button 3X3. The operation of button '3XBB closes an obvious pick-up circuit. for relay BS at contact operator actuates button BP relay,-BS;.

From the above explanation it will be apparent that the actuation of exit button 3X13 in combination with entrance button ZNB, completes the circuit for relay 23 at contact 15. Furthermore, since contacts and 85 of buttons 3XBA and fiXBB are in multiple with contact 15, the actuation of either of these auxiliary buttons completes the route circuit andin addition controls the operation of the indication as before.

Fig. ;3 modification-The modification disclosed in Fig. 3 uses auxiliary completion buttons 3XBA and SXBB which correspond to buttons 3XBA and BXBB of the disclosure of Figs. 2A and 2B.

In this modified arrangement, the actuation of button 3XBA to announce an A train does not immediately pick up relay AS (corresponding to relay AS of Fig. 2B), but it does pick up relay AK by an obvious circuit closed at contactv52. Relay AK closes a stick circuit for itself extending from front contact 53 of track relay 7T (corresponding to relay IT of Fig. 2A), normally closed contact of button ACP, front contact 39 and winding of relay AK to Therefore, relay AK will remain picked up as long as the track relay is energized and push button ACP is in its normal position.

When the train passes onto the track section with which relay 'ET is associated, the dropping of this relay closes a circuit for picking up relay A8 extending from back contact 53 of relay l'TLIfront contact 55 of relay AK and winding of relay AS to The operation of relay AS .closes a stick circuit for itself including the normally closed contact of button AP front contact .63 and Winding of relay AS to The closure of front contact 65 of relay AS lights lamp AL to give the operator the information that the train is an A class train.

Relay AK is a stick relay of the slow releasing type,'jso that it will be energized in response to the momentary actuation of button 3XBA and remain energized long enough after relay 1T drops to permit relay AS to pick up. Relay AK drops to its normally deenergized position shortly after track relay 7T is deenergized.

The purpose of button ACP is to permit the operator to cancel a train identification in the event that an error is made by actuating the wrong completion button. It will be observed that this cancellation can be effected providing the error is noticed and corrected before the train passes onto the track section and drops relay 1T since relay A5 is not picked up for lighting lamp AL until this section becomes occupied. 7

It is not believed necessary to point out the circuits for and explain the operation of completion button 3XBB in detail, since this circuit organization functions in a manner exactly the same as that explained in connection with button 3XBA It will be appreciated that considerable advantage is effected by this invention, whereby one act on the part of the operator serves both to complete the NX route and announce the identity of the train for which the route has been setup. If he were required to perform two acts, it would increase the manual effort required and furthermore would increase the likelihood of his failure to transmit the identity of the train.

Having thus described a centralized trafiic controlling system for railroads as one specific embodiment and one modification thereof, it is to for deenergizing be-understood that'various modifications, adaptations :andalterations may-be. applied to meet the requirements of practice without in any manner departing from the spirit or scope of the invention except as limited by the appended claims.

.one ;of said routes, and means responsive to the particular one of said common exit buttons which is operated for indicating the class of train traversing saidrparticular route.

2. In an interlocking system for railroads, a track layout comprising a plurality of routes having a common exit, entrance butttons for the entrances for said routes, a plurality of exit buttons for said common exit, means for setting up a route' in response to the joint operation of the entrance button for that route and any one of said common exit buttons, and a plurality of indicators selectively activated in accordance with the common exit button operated.

3. In a railway signalling system, a first location in said system comprising an interlocking plant with a plurality of routes-each having its individual entrance and having a common exit, a second'location insaid system at which trains of different classes arrive from said first location, an entrance button at said first location for each of said entrances, afirst exit button and a second exit button for said common'exit, means for setting up a route in response to the joint operation of the entrance button forthat route and either said first exit button or said second exit button, a first indication relay operated by said first exit button, a second indication relay operated by said second' ex'it button, and means controlled by said first and said second indication relays for controlling first and second indicators respectively to indicate the precursory arrival of trains of first and second classes.

4. In a railway signalling system, a first locationin said system comprising an interlocking plant with a plurality of routes having entrance points and a common exit point, a second location in said system at which trains of diiferent classes arrive from said first location, an entrance button at said first location for each of said entrance points, a first exit button and a second exit button at said first location for said common exit point, means for setting up any one of a plurality of routes in response to the joint operation of the entrance button for any one of said plurality of routes and either said first exit button or said second exit button, a first indication relay at said second location operated by said first exit button, a second indication relay at said second location operated by said second exit button, and means controlled by said first and said second indication relays for controlling first and second indicators respectively to indicate the precursory arrival of trains of'first and second classes at said second location.

5. In a railway signalling system, a first location in said system comprising an interlocking plant with a plurality of routes having entrance points and a common exit point, a second locationin said system at which trains of difierent classes arrive from said first location, an entrance button at said first location for each of said entrance points, a first exit button and a second exit button at said first location for said common exit point, means for setting up any one of a plurality of routes in response to the joint operation of the entrance button for any one of said plurality of routes and either said first exit button'or said second exit button, a first indication relay at said second location operated by said first exit button, a second indication relay at said second location operated by said second exit button, means controlled by said first and said second indication relays for controlling first and 7 second indicators respectively to indicate the precursory arrival of trains of first andsecond classes at said second location, manually controlled push buttons associated with said indication relays, and means for maintaining said indication relays operated when once operated until released by said manually controlled push buttons.

6. In a railway signalling system; a firs-t location in said system comprising an interlocking plant with a plurality of entrances and having a common exit; a second location in said system at which trains of different classes arrive from said first location; an entrance button at said first location for each of said entrances; a first exit button and a second exit button at said first location for said common exit; means for setting up a route in response to the joint operation of the entrance button for that route and either 7 said first exit button or said second exit button;

a first indication relay at said second location having its circuit prepared by said first exit button; a second indication relay at said second location having its circuit prepared by said second exit button; train controlled means for completing said prepared circuits, wherebysaid indication relays are operated; and means controlled by the operation of said indication relays for controlling visual indicators to indicate the precursory arrival of trains of first and second classes at said second location.

, '7. In an interlocking system for railroads, a track layout having a plurality of routes, some of said routes having common ends, manually operable control means for each of saidroute ends,

means responsive to the operation of said manually operable control means for the opposite ends of a route to set up and clear that route, and means controlled by the operation of said manually operable control means at the leaving end of such routeto indicate at a distant point expected arrival of a train.

8. In an interlocking system for railroads, a track layout having a plurality of routes, some of said routes having common ends, manually operable control means for each of said route ends, certain said control means having distinctive operated conditions, means responsive to the operation of said manually operable control means for the entrance end of a route and the distinctive operation of said manually operable control means for the leaving end of such route to set up and clear that route, and means controlled by the distinctive operation of said manually operable control means at the leaving end of such route to indicate at a distant point expected arrival of a particular distinctive class of train.

9. In an'interlocking system of the entranceexit type; the combination with a track layout for establishing a plurality of routes, some of which routes have common entrance points and some of which routes have common exit points, a plurality of control buttons for each entranceexit point, means responsive to the joint operation of a button for an entrance point and a particular button of the plurality of buttons for an exit point for establishing a route connecting corresponding points, a plurality of indicators one for each button for such exit point, and means for rendering active that indicator corresponding to the particular button operated at said exit point.

- SEDGWICK N. WIGHT.

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