US2241958A - Railway signaling - Google Patents

Description

May 13, 1941. G. R. PFLSTERER RAILWAY SIGNALING Filed March 16, 1939 w I l vENToR (wo/2g@ 19.?

[IIS ATTO R N EY Patented May 13, 1941 UNiTED STATES OFFECE RAILVAY SIGNALING Application March 16, 1939, Serial No. 262,211

'13 Claims.

My invention relates to railway signaling, and particularly to an arrangement involving wayside signals located along a trackway for governing the movement of trains.

One feature of my invention is the provision of novel and improved means for displaying a distinctive permissive indication at the entrance to an occupied block or stretch of track, so that a train may enter such block. or stretch of track without stopping, and for displaying a stop indication if the permissive indication is not displayed when it should be.

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

The accompanying drawing is a diagrammatic view showing one form of railway signaling embodying my invention for the control of signals of a type, such for example as searchlight signals, having a mechanism operable to various positions for cooperating with a lamp to display corresponding indications.

Referring to the drawing, the reference characters 4 and 4a designate the rails of a stretch of railway track over which traiic normally moves in the direction indicated by the arrow, which I shall assume is the eastbound direction. Rails 4 and 4a are divided by insulated joints 5 into blocks af-b, b-c, etc.

Each of these blocks as shown is further divided by other insulated joints 5 into two sections, 4

block c b, for example, being divided into sections IT and AIT. It is not necessary, for the purpose of my invention, that the blocks be divided as shown. In some instances it might be satisfactory to have only one section for each block, and in other instances it might be necessary to divide each block into more than two sections. Each track section is provided with a track circuit including a battery 6 connected across the rails adjacent one end of the section, and a relay, designated by the reference character TR with a distinguishing prefix, connected across the rails adjacent the opposite end of the section.

Adjacent the entrance end of each of the blocks, such as at ct, b and c, a signal is located for governing eastbound tralc movements into the corresponding block. These signals are designated by the reference characters I, 2' and 3, respectively. As here shown, each of the signals is of the searchlight type, but may be of any other suitable design.

Each of the signals as shown comprises a control member or mechanism 1 mounted to oscillate between two extreme positions, and controlled by a control winding 8 and by a permanent magnet or an electromagnet not shown, so that when winding B is energizer, member 1 will move to one of its extreme positions or the other according as winding 8 is energized by current of normal or reverse polarity. Member 1 is biased toward a middle position, which it occupies when winding 8 is deenergized. Member 1 carries three roundels G, R and Y arranged to cooperate with a signal lamp, designated by the reference character E with a numerical prex corresponding to the reference character for its signal, in such manner that when member 1 is in the middle or stop position, roundel R is in front of lamp E, Whereas when member 1 is swung to the left or to the right into a caution or a proceed position, roundel Y or roundel G, respectively, is placed in front of lamp E.

As shown in the drawing, lamp E is above the roundels, but the lamp is placed in this location for purposes of illustration, and it is to be understood that in actual practice, the lamp is directly behind the roundels.

Each of the signalsoperates a contact 9, which is closed when roundel Y is placed in front of lamp E, but is open when roundel G or R is placed in front of lamp E.

A signal of this type is disclosed and claimed in Letters Patent of the United States No. 1,864,224 granted to Wesley B. Wells on June 21, 1932, for Light signals.

Associated with each signal is a polarized signal relay designated by the reference character HD preceded by a number corresponding to the reference character for its signal. The I-lD relays are of the retained neutral type, that is, the front contacts of these relays are slow to release, so that they do not open during an operation of the polar contacts of these relays from either extreme position to the other.

. Also associated with each signal, are two neutral relays, comprising an approach control delay designated by the reference character ER with a prefix corresponding to the reference character for its signal, and a checking relay of the slow release type designated by the reference character XR preceded by a number corresponding to the reference character for its signal.

Also associated with each signal, is a flasher relay designated by the reference character F with a prefix corresponding to the reference character for its signal. Each of the fiasher relays F is provided with contacts designated by the reference characters II and I2, respectively, which are biased toward the normal position in which they are shown, when their relay F is deenergized, but which are periodically operated to the dotted line position, shown to the right of the normal position, when their relay F is energized. Each contact I I is therefore constantly closed when the relay F by which it is operated is deenergized, and is periodically closed when its relay F is energzed. Each contact I2 is open when its relay F is deenergized,-but becomesclosed periodically when its relay F is energized.

The winding 8 of each signal is energized by normal and reverse control circuits controlled sby the associated signal relay I-ID, when the block for its signal, which is the first block in advance of its signal, is unoccupiedlorclear. Windingy of each'signal is also energized: by aiv second" re- Verse control circuit controlled by a front; contact of the associated checking relay and by Vback contacts of its signal relay when its block is occupied by a train.

The lamp E for each signal is lighted by a cirbcuitwhich is controlled vby aback contact of the associated approach' control relay, when the neXt block in the rear of its'lsi'gnal is occupied, ,and by the contact II of 'the'associated flasher relay F. rEach' signal relay HD isenergized only if the rblock'for its signalis unoccupied,.and is..ener

gized by current of .normal .orreverse polarity .according as` the HD relay.for the next signal .in

advance is energized or deenergized.

Each approach control' relay ER is venergized by current of a given polarity in.series with the vsignal relay'HDLfor the .next signal in the rear.

Each checking relay XR has aiirst energizing circuit.. controlledby vaffront contact of the associated approach'control relay ER; ,a second .energizing circuit controlled by a back ycontact of the associated approach control relay'ER-and by a. frontcontact of .the associated HD relay; and va. .third energizingy 'circuit controlled ,by .the contact I2 of the associated flasher relay F.

Each ilasher relay F is energized `when the vfirst block in the rear and the rst block. in advance .of itssgnalV are bothoccupied `and the v.member Lof the Yassociated ,signalis in vthe posi- ,tionin. which,` inconjunction with the lampE for its signal, it displays a ye1low..indication on account of its roundel ,Y- being in front of ,lamp E for its signal.

As shown inl-the drawing, ,.Ytraoksection 3T,

immediately in advance of signal 3,"is occupied :byea trainW. The indication displayed byv each of the signals= I;Y tof3,' inclusive,` unclerthisv condition, v`whenY a' 'second train roccupies the' next `block -in`4 thecrear-of each" of' these vsign-als suc- :cessively, and the meaningszoi"r these 'indications -are` stated inv theffollowingtable:

'Signal Indication displayed Meaning 'of indication l Green Q Proceed. 2 Constant yellow Prepare: 'to stopat" next l signal. 3 i Flashing'yellow V:Proceed at restrictedspecdy block is occupied. Constant red would be dis- Stop and. proceed. "played instead 'of flashing yellowif relay 3F-1shonld be falsely deenergized.

lamps E is shown lighted as it would be lighted if a train occupied the rst block in the rear of its signal while no other section shown in the drawing is occupied except section 3T, which is occupied by train W.

As shown in the drawing, when a first train occupies section 3T, signal I will display a constant green indication if a second train occupies section OIT in the rear of signal I; signal 2 will display a constant yellow indication if the second train occupies the block a-b instead of section OIT; and signal 3 will display a flashing yellow indication if the second train occupies signal 3 will display a constant red indication I shall now describe the manner in which these indications are displayed While a first train W occupies section 3T, as shown in the accompanying drawing, with a second train in the next .block inthe rear of the Various signals.

kWith train Woccupying section 3T, relay STR isdeenergized and, hence its contact I5 is open, thereby deenergizing relay '3l-ID. If, as shown in the drawing, there is. no train in block b-c, relays 3ER and ZHD will be energizedby a circuit passing from terminal B of a suitable source of current, through the winding of relay 3ER, back point of Contact I6 of relay 3m, winding of relay' 2I-ID, contact I5 of relay ZTR, Contact I4 of .relay AZTR, and the back` point of contact I3 'of relayv SHD to terminal 0 of the same source of current. With relay 3ER thus energized, relay SXR is energized yby its rst circuit, passing from terminal B, through ,the frontpoint of contact I7 of relayy SERWand the winding of relay SXR to terminal. 0. With relay 3XR thus energized, winding 3.,of.signal.3 is energized Yby currentof reverse polarity passing from terminal B, through cont-act' I9 of relayXR, back point of contact 22 of relay `SHD, winding ofsignal 3, and back point of contact 23 of relaySHD to terminal With winding 8 thus. energized byV a reverse control circuit, roundelYof signal3 isin front of lamp 3E, and hence rcontact 9 of signal 3 is .closed With relayv 3ER energized, however,` the circuit for energizing relayr 3F is open at the-back point of contact Ilof relay.3ER,land the circuit for energizing lamp 3E of signal 3 is open at con'- tact I IJof relay 3ER.

Relay 2HD is energized bycurrent of reverse polarity. in the, circuit previously .traced forI relays SER and ZHD. With relay ZHD thus energized, av circuitincluding relays IHD and 2ER is completed for .energizing relay IHD. bycurrent of normal'polar,ity, this circuit passing from terminal B, through. the winding of relay. 2ER, front pointof contact I3 of relay ZHD, contacts lli'.` and I5,ofv relays AITR and I TR, respectively,

Winding of relay IHD, and the frontpoint of I contact I6 of -relay ZHD to terminal ITI. With relay 2ER energized, relay-2X3 Ais energized Aby ya circuit whichissimilar to that previously traced for relay.3XR. With, relay ZHD energized by current ,of reverse polarity, Awinding- 8 of signal 2. is .energized in the reverse direction by acircuit -passing from Yterminal B, through contact .2li of relay., 2HD closed in theright-h-and vposition, front point :ofvcontact 22 of relay ZHD, winding t of signalZ, front point of contact 23 of relay ZHD, and contact ZI ofA relayv '2l-ID closed in the right-hand position, to terminal 0. Roundel Y of signal 2 is therefore in front of lampZE. With relay 2ER energized, asher re- .layv 2F and lamp 2E are deenergizedatl the back points of contacts I'I and III, respectively, of relay 2ER.

With the Winding of relay II-ID energized by current of normal polarity by the circuit traced for relays IHD and 2ER, winding 8 of signal I is energized by current of normal polarity passing from terminal B, through contact 2| of relay IHD closed in the left-hand position, front point of Contact 23 of relay IHD, winding 8 of signal I, front point of contact 22 of relay IHD, and contact 2B of relay IHD closed in the lefthand position, to terminal IJ. If there is no train in the next block to th-e rear of signal I, relay IER will be energized, and hence relay IXR will be energized by a circuit which is similar to the circuit previously traced for relay SXR. With winding 8 of signal I energized by current of normal polarity, roundel G of signal I is in front of lamp IE.

I shall assume that a second train enters the first block in the rear of signal I, causing relay IER to become deenergized. With relay IER deenergized, Contact I'I of this relay Will be opened at its front point, and hence the rst energizing circuit for relay IXR will be opened.

Relay IXR will, however, now be energized by its second energizing circuit, passing from terminal B, through the back point of Contact I'I of relay IER, front point of contact I8 of relay IHD, and the winding of relay IXR to terminal I). With relay IER deenergized, a circuit is now completed for constantly lighting lamp IE, this circuit passing from terminal B, through contact I of relay IER, contact II of flasher relay IF, and lamp IE to terminal Il. Signal I Will therefore display a constant green or proceed indication.

I shall next assume that the second train passes signal I, entering block a-b and deenergizing relay ITR, contact I5 of which then opens, thereby deenergizing relays IHD and 2ER. Relay IHD, upon becoming deenergized, opens, at the front point of its contact I8, the second energizing circuit previously traced for relay IXR. Relay IXR, being of the slow releasing type, does not, upon becoming deenergized, permit its contact I9 to open immediately.

Relay IHD, upon becoming deenergized, therefore completes a circuit for energizing winding 8 of signal I by current of reverse polarity, this circuit passing from terminal B, through contact I9 of relay IXR, back point of contact 22 of relay II-ID, winding 8 of signal I, and back point of contact 23 of relay IHD to terminal 0. Member 'I of signal I will then move to the caution position, closing its contact 9 :and thereby completing a circuit for energizing iiasher relay IF, passing from terminal B, through the back points of contacts I'I and I8 of relays IER and IHD, respectively, contact 9 of signal I, and the winding of relay IF to terminal Il.

Contact I2 of relay IF then periodically closes the third energizing circuit for relay IXR before contact I9 of this relay has opened on account of its second energizing circuit having been opened. On account of relay IXR being of a slow releasing type, contact I9 of this relay will be retained in its closed position during the open periods of contact I2 of relay IF. The circuit previously traced for lighting lamp IE will now be periodically opened at contact II of relay IF, causing signal I to display the dashing yellow or permissive indication.

When the second train leaves section OIT, relay IER will again become energized and open the circuits previously traced for energizing relay IF and lamp IE. Relay Dm Will now be retained in its energized condition by its first energizing circuit including the front point of contact I"I of relay IER.

With relay 2ER deenergized, the *first energizing circuit for relay ZXR will be opened and its second energizing circuit will become closed, similarly to the corresponding circuits previously described for relay lIXR. With roundel Y of signal 2 in front of lamp 2E, contact 9 operated by signal 2 is closed, but the energizing circuit for asher relay 2F is open at the back point of contact I8 of relay ZHD, and hence relay 2F is deenergized. With relays 2ER and 2F deenergized, lamp 2E for signal 2 will be lightedby a circuit which is similar to the circuit previously traced for lamp IE of signal I. Lamp 2E will therefore be constantly lighted, :and signal 2 will display a constant yellow or caution indication.

I shall now assume that the second train passes signal 2 and enter-s block b-c, thereby deenergizing relays ZHD and 3ER. The reverse energizing circuit previously traced for winding 8 of signal 2 will now be opened at the front points of contacts 22 and 23 of relay ZI-ID, :and the second reverse energizing circuit for this winding, which is similar to the reverse energizing circuit previously traced for Winding 8 of signal I, will be completed at the back points of contacts 22 and 23 of relay ZHD. The circuit for energizing relay 2F, which is similar to the circuit previously traced for relay IF, will now be completed at the back point of contact I8 of relay 2I-ID. Signal 2 will then display the flashing yellow or permissive indication until the second train leaves block a-b.

With relay 3ER deenergized, the first energizing circuit traced for relay 3XR will be opened at the front point of Contact I'I of relay 3ER, and the energizing circuit for relay 3F, which is similar to the circuit previously traced for relay IF, will be completed at the back point of contact I'I of relay 3ER.v Relay 3XR will now he retained in the energized condition by its third energizing circuit including contact I2 of relay 3F. Lamp 3E will be periodically lighted, and signal 3 will thus display the flashing yellow or permissive indication.

If, for any reason, flasher relay 3F should be falsely deenergized, causing its, contact II to remain constantly closed and its contact I2 to remain constantly open, relay 3XR will become deenergized, thereby opening, at its contact I9, the circuit for energizing winding 8 of signal 3 in the reverse direction, and causing roundel R of signal 3 to be moved in front of lamp 3E. With relays 3ER and 3F deenergized, lamp 3E will be lighted by a circuit which is similar to the circuit traced for lamp IE, and hence signal 3 will display a constant red indication.

From the foregoing description and the accompanying drawing, it follows that in railway signaling apparatus embodying my invention, I have provided means for controlling a signal for governing traffic movements into a given block, section, or stretch of railway track, to display a constant indication for authorizing a traffic movement to be Inacle into they associated portion of track, to display a flashing indication if the associated portion of track is occupied and the signal mechanism occupies a position for authorizing a traii'ic movement into the portion of track, and to display a constant stop indication if the flashing means should be falsely deenergized" While the associatedf portionof :trackiszocficupied.

Although I` have hereinV shown and described ',-only one form of railway signaling embodying my invention, it is to be understood that various changes. and modifications may bemade therein -Within the scope of the appended ,claims without departing from the spirit. and scope ofmy invention.

Having thus described my invention, what I claim is:

ll. 'In combination, a stretch of railway track divided into blocks, a signal for each of said blocks comprising a signal lamp and a sign-al mechanism biased toward a stop position but ,operable to a proceed and a caution position for cooperating with said signal lamp for governing traiiic movements into the associated block when 'said sign'al lamp is lighted, a signal relay for each of said signals, train responsivemeans for energizing each of said signal relays only if the lblock for the associated signal is unoccupied and for energizing each olf said sig-nal relays by current of normal or reverse polarity according as the next block in adv-ance of the block for :the a'ssocia'ted signal is unoccupied or occupied, an approach control relay for each of said signals energized in series with the signal relay for the next signal in the rear, a checking relay for each signal, a circuit controlled by a front contact of each approach control relay for energizing the checking relay for the same signal, a second `circuit controlled by a back contact of each approach controlrelay and by a front contact of the sig-nal relay for the same signal for energizing the checking relay for the same signal, a 'asher relay for each signal having a normal contact constantly closed while i-ts flasher relay is deenergized and periodically closed while its asher relay is energized and having a reverse contact which is periodically closed while its asher relay is energized, a third circuit for energizing each checking relay controlled :by the reverse contact of the asher relay for the same signal, .a circuit for energizing each of said asher relays controlled by ya back contact of the approach control relay and by a back contact of the lsignal relay for the same signal and also by a contact closed by the mechanism of the same vsignal when such mechanism occupies the caution position, a circuit for lighting lthe lamp for each signal controlled by a back contact of the approach control relay and the normal contact of the asher relay for the same signal, vmeans controlled by the signal relay for each signal when energized by current of normal or reverse polarity for operating the mechanism for the same signal to the proceed or the caution position respectively, and means controlled .by a front contact of the checking relay for each signal for operating the mechanism-for its signal to the caution position While the associated signal relay i's deenergized.

2. In combination, a stretch of railway track divided into blocks, a signal for each of said blocks comprising a signal lamlp and a signal mechanism for cooperating with said signal lamp when said signal lamp is lighted for governing traffic `movements into the associated block, a slow release checking relay for each of said signals, a flasher relay for each of said signals having a normal contact constantly closed while the corresponding flasher relay is 'deener'gized and periodically closed while the corresponding flasher relay is energized and having a reverse contact lwhich is periodically.closeduwhile .the icorrespending vflasher relay is energized, trafficvrespon- 'sive means for energizing each checking'relay if there is no train in thenext :block inthe rear/of the associated signal o-r if 'there is no train in the block for the associated signal While thetnexlt blo'ck in the rear is occupied, means for each signal controlled by the reversefcontact ou its flasher relay for Ialso energizing its checking relay, t-raic responsive means for conditioning fthe `signal mechanism of each signal for'rcoopera'tin-g .with its lamp for displaying an indication for authorizing traino movements into .its block if its block is unoccupied, means for each signal control-led by ai front contact of its checking .relayandby traic responsive means for lalso conditioning its mechanism for cooperating with its lamp forrdisplaying .a permissive indication if its' ylolockrfis occupied, trafc responsive means .and means controlled by 4the mechanism of each signalfor energizing the flasher relay for vthe corresponding signal when the first block in advance and the' rst block in the rear'of the corresponding signal are both occupied, and means controlled by the normal Contact of each flasher relay and by 'traffic responsive means for lighting the lamp for the associated signalwhen the next block in the rear is occupied.

3. In combination, a stretch of railway track divided into blocks, Ia signal at the entrance end of each of said blocks comprising -a signal lamp and a signal mechanism operable to various positions for cooperating with said signal lamp to" display various vindications for governing trailic movements into the associated' first block `in advance, a flasher relay for each of said signals each having a rst contact constantly closed while `its flasher relay is deenergized and vperiodically closed whileits flasher relay is energized, a second contact'operated by each of said flasher relays each periodically closed while: its flasher relay is energized, a slow release checking relay for each of said signals, traffic responsive means vfor energizing each'of said checking relays while the Unlock for the associated signal is clear, a `circuit for each signal controlled by the second contact of its flasher relay for also energizing vits checking relay, means `controlled by traffic conditions in advance of each signal for operating .the mechanism for each signal to a Vfirst or la second position-according as the first two blocks inadvance of the-corresponding signalare clear-.or the irst block in advance is clear while the second block `in 'advance is occupied, means for each signal vcontrolled-by afront contact of its'checking relayfand by traiiic conditions for also operating its 'mechanism to the second-position if :the rst block in advance of the signal is occupied, means controlled by a contact of each signal closed 'while the mechanism ffor the correspon-ding signalocculpies the second vpotion and controlled by traicconditionsfor energizing the yassociated asherrelay while the first block in advance 'oli the'corresponding signal is occupied, and means for each 'signal controlled by the first ,contact of its asher relay forlighting its lamp.

4. In combination, a stretch of' railway track divided into blocks, a signal for each of said blocks comprising a signal lamp and a signal mechanism operable to various positions for cooperating with said lamp to display various indications for governing trafc movements into the associated block, means controlled by traic conditions for operating each of said sign-al mechanisms to a given position for authorizing traic movements into -the associated block if the associated block is unoccupied, train responsive apparatus associated with each of said blocks, means for energizing said train responsive apparatus if the associated block is occupied, means controlled by said train responsive :apparatus for operating the mechanism for each signal to a permissive position While the associated block is occupied, means controlled by traflic conditions for constantly lighting the lamp for each signal while the associated block is clear, and means controlled by said train responsive apparatus for periodically lighting the lamp for each signal While the associated block is occupied.

5. In combination, a stretch of railway track divided into blocks, a signal for each of said blocks for governing traiiic movements into the associated block, control means for each of said signals, means controlled by traiiic conditions for energizing the control means for each of said signals in a given manner if the next two blocks in advance of the corresponding signal are unoccupied and for energizing fthe control means for each of said signals in a second manner if the first block in advance is unoccupied but the second block in advance is occupied, means controlled by a train upon passing each of said signals for also energizing the control means for the corresponding signal in said second manner, and means controlled by the control means for each of said signals and by traffic conditions for controlling the corresponding signal to display a constant indication if its control means is energized in said iirst or said second manner while the first block in advance is unoccupied and for controlling the corresponding signal to display a periodic indication if Ithe control means is energized in said second manner while the iirst block in advance is occupied.

6. In combination, -a stretch of railway track divided into blocks, a signal for each of said blocks comprising a signal lamp and a signal mechanism operable to various positions for cooperating with said signal lamp to display various indications for governing traic movements into the associated first block in advance of the corresponding signal, means controlled by traffic conditions for operating each of said signal mechanisms to a proceed position or la caution position according as the iirst two blocks in advance of the corresponding signal are clear or the iirst block in advance is clear While the second block in advance is occupied, =a checking relay for each of said signals, means responsive to traffic conditions for energizing each said checking relay while either the iirst block in the rear of its signal or the first block in advance of its signal is clear, means controlled by each of said signal mechanisms and by rtraiiic conditions for energizing the associated checking relay ii its signal mechanism occupies the caution position while the iirst block in the rear of its signal and the iirst block in advance of its signal are both occupied, means controlled by a front contact of each checking relay and by traffic conditions for retaining the associated signal mechanism in the caution position while a train occupies the iirst block in advance of the corresponding signal after entering this block While its signal mechanism is in the caution position, and means controlled by each of said signal mechanisms and by traine conditions for constantly lighting the associated signal lamp While the first block in advance of its signal is clear and for periodically lighting the associated signal lamp While the rst block in advance of its signal is occupied.

7. In combination, a stretch of railway track divided into blocks, a signal for each of said blocks comprising a signal lamp and a signal mechanism operable to various positions for cooperating with said lamp to display various indications for governing traflic movements into the associated block, means controlled by traflic conditions for operating each of said signal mechanisms to a rst or a second position for authorizing traflic movements into its block according as its block and .the next block in advance of its block are both clear orl its block is clear and the next block in advance is occupied, means controlled by trafiic conditions for also operating each of said signal mechanisms to its second position if its block becomes occupied, means controlled by each of said signals for retaining its mechanism in the second position while its block is occupied, and means controlled by each of said signals and by trafc conditions for constantly lighting the lamp for the corresponding signal While its block is clear and for periodically lighting the same lamp while its block is occupied and its signal mechanism is in said second position for authorizing traiiic movements into its block.

8. In combination, a stretch of railway track including a given block, `a. signal for governing traiiic movements into said block, signal control means for said signal, means controlled by trafllc conditions for energizing said signal control means while said block is unoccupied, a slow release checking relay and a flash-er relay, a circuit for energizing said checking relay including a contact closed if said block is unoccupied, a second circuit for energizing said checking relay closed if said flasher relay is energized, means controlled by a front contact of said checking relay and by traffic conditions for energizing said signal control means if said block is occupied, a circuit for energizing said iiasher relay closed by said signal control means in its energized condition while said block is occupied, and means controlled by said ilasher relay for controlling said signal to display a constant indication while said block is unoccupied and for controlling said signal to display a periodic indication if said block y is occupied while said signal control means is energized.

9. In combination, a stretch of railway track including a given block, a signal comprising a signal lamp and a signal mechanism operablel to authorizing and stop positions for cooperating with said lamp to display indications for authorizing traic movements into said block or for stopping such traiiic movements respectively, means controlled by traffic conditions for operating said signal mechanism to an authorizing position While said block is clear and for conditioning said mechanism for also occupying lan authorizing position after a train enters said block, means controlled by said signal mechanism and by traic conditions for constantly lighting said lamp if said block is unoccupied or if said signal mechanism occupies its stop position `and for periodically lighting said lamp if said block is occupied while said mechanism is in an authorizing position, and means associated with the control for said lamp for deenergizing said mechanism if said lamp is controlled to be "constantly lighted when it should be periodically :lightedl mechanism for effecting its operation to said proceed or said caution position according as said rstv and second blocks are both unoccupied or said Vfirst block is unoccupied while said second `lolockris occupied and for conditioning said mechanism to also occupy said caution position when said rst-block-is occupied, train controlled lighting 'means for constantly lighting said lamp while saidmechanism occupies its'proceedor its stop positionand also when` said'mechanism occupies its :caution position while-said rst block is unoccupiedrbut forA periodically lighting said lamp When-.said'mechanism` occupies its caution position. while 'saidrst block is occupied, and means controlled in conjunction with said lighting means. for-deenergizing said signal mechanism if Saidlighting means isfcontrolled -to constantly light said lamp when it should be controlled to periodically light said lamp While said rst block is occupied.

11'.I .[n-4 combination, a stretch of railway track including agiven block, a signal comprising a signallampand a signal mechanismv operable to a plurality of-positions for cooperating with said lamp to display various indications for .governing trac movements into said block, means ycontrolled -by-trac conditions for operating said signal .mechanism for authorizing traiiic movements intoisaid block while vsaid block is clear, means controlled .by `traiic. conditions as a train enters said block for operating saidI signal mechanism to` a--given position for-authorizingftraic movements into said block, means controlled by said signal mechanism after being operated to` said. given.- position for retaining said signal mechanism-in said given position while a train occupies said block, and means controlled by said signal /mechanism andby traiiic conditions Vfor constantly lightingsaid lampif said block is unoccupied Sand for -periodically lighting said lamp if said blockis voccupied while said mechanism is in` said given position for authorizing traic movements into said block.

12;'Incombinatiomv a stretch'of railway track including-a-given block, a signal `comprisingl a signal vlamp and a signal mechanism capable of beingconditioned for cooperating with sai-dflamp to display 4various indications Vfor governing trafc movements into said block, means controlled by -trane conditions in said block-for conditioning said. signal .mechanism for authorizing traiiic movements into said block; a 'slow release check-f. ing relay, a lcircuit responsivey .to traffic conditions. in said stretch` closedfonly :if isaid"blockI-:isuunoccupied for energizing said:checkingnrelaypa cir-U cuit controlled by-a front--contactofrsaidf check-1Y ing relay for :conditioning said signal mechanism'. for also authorizing tran-lc movements :into said; block when said block becomes occupied; aflashery relay, a circuit controlled'byj-trafc conditions'. and by said signal mechanism'for energizing-said'E flasher relay if said block -is occupiediwhilesaidt signal mechanism is infia lconditi'on'iorauthor-- izing traffic movements Vinto said/block, afsecond. circuit yfor energizing said checking-v relayclosedA by said ilasher relay while said 'flasher relayis. energized, and a circuit controlled by said flasher relay for constantly lighting said lamp whilefsaid asherf relay is f-deene-rgized .and for periodically. lighting said lamp While said asher relay is en'- ergized.

13. In combination-a stretch of railway track-y divided into a iirst and a-secondsection, a-signalI comprising-iy a` signalv lamp .and a signali-nfiecha nism capable of vbeing-conditioned for cooperating with said lamp to display various indicationsy for governing traffic movements from said 'first' section into said second section, train responsiveL apparatus for saidv first section, trainrresponsive apparatus forsaid second section, means :controlled by saidtrain responsive apparatus fon: said second section for conditioning said signalrnechanism for authorizing traiic movements intosaid second section-if said second'sec-tion is funoccupied, a checking-relay, a circuit controlled by said train responsive apparatus forV saidrst section for energizing said-checking relay if4 said nrst section-is unoccupied,^a second. circuit con-1 trolled by said train responsive apparatus for said first .and-second sections for energizingA said checking relay if said first section is occupied" While said second sectiony is unoccupied, a asher relay, a-third circuit controlled by said train responsive apparatusl for saidrst and second secl tions and by said signal mechanism for energiz-V4 ing -said-iiasher relay if said second section is ocf cupied-.while said iirstI sectionl is occupied yand said signal mechanism' is in aicondition for aul thorizing.V traflic movements into said stretchifa. fourth circuitcontrolled byl said iiasher relay for energizing f saidy checking `relay gwhilevsaid flasher relay'is energized, meanscontrolledby a-front contact' of said checking-.relay and by said train-r responsive :apparatus for said secondsectionfor conditioning said signal mechanism for 'authoriz-z ing traffic movements into said ,secondfsectionv while saidsecond section is occupied,.and means.` controlled bysaidA flasher relay for constantlyf lighting saidy lamp 'While' said flasher relay isideenergized and for periodically `lighting said v lamp. i while said=flasher relay isenergized.VV

GEORGE Rf:1:FLAS'lIEJFtER...l

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