US913557A - Block-signal system. - Google Patents

Description

G. S. PFLASTBRER.

BLOCK SIGNAL SYSTEM.

APPLICATION FILED JUNE o. 190s.

Patented Feb. 23, 1909.

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G. S. PIFLASTBRER. BLOCK SIGNAL SYSTEM. APPLIOATION FILED JUNE 9, 1908.`

Patented Feb.23,19o9.

3 SHEETS-SHEET 2.

G. S. PFLASTERER.

BLOCK SIGNAL SYSTEM.

APPLICATION FILBDAJURE 9, 1908.

Patented Feb. 23, 1909.

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III'IIIIIIIIIH UNITED stra-ras GEORGE s. PrLasrnRfrinL. or NASHVILLEfTnNNnssnE.

BLOCK-SIGNAL SYSTEM. y

.Application led June 9,

To all .whom it may concern Be it'knovvn that l, .GEORGE S. PFLAs- TERER, a citizen-oiy the United States ot' America, residing in Nashville, in the county of Davidson and State otrlennessee, have invented a certain new and useful lmprovement in Block-Signal Systems, of which the following is a true and exact description, reference being had to the accompanying drawings, which form a part thereof.

The present invention relates to railway block signal systems and particularly to block signal systems 'for single track rail- Ways.

N One main object of the invention is to provide a reliable, eiiective and relatively simple block signal system of the kind described Whieh can be cheaply installed and is inexpeps'ive tomaintain.

Ihe preferred 'form of thesystem which l have devised is electrically controlled and vmanually operated andreseinbles the well provided the latter has proceeded apredet'ermined distance from the end ol the block at Which it entered. The invention however is notl limited in all of its aspects to a system having proyisions for permissive signaling. The signal circuit may in the block either through short insulated track sections or a continuous track circuit, though the latter alone is disclosed herein.

-By preference also, as illustrated herein, each r'signal proper is actuated through an eleetrhl slot controlled mechanism arranged to return the"signal to danger whenever either the front end or the rear end of a train entering the block passes by the signal. y ln the particular system disclosed in detail herein front end control oi" the slot magnets is had,v

One important,feature ol the particular form oi apparatus disclosed is loundin the i 'fact that every signal clearing operation Specification of Letters Patent.

be controlled by' trains Patented Feb. `23, 1909. i908. serial Ne.'437,542.

l whether absolute or permissive requires the i permission and cooperation of the operators at both ends of the block and another .iinportant feature of this apparatus is found in the arrangement for preventing any signal from being cleared until a train is inproximity thereto preventing the operator from rcarelessly anticipating train movements.l

The invention also comprises arrangements by which the opening of the switches or sidings joining the main track of the blocks automatically brings to danger if cleared -and regulates the clearance of the main signals at the block ends, and by which train movements from the station switches or intermediate switches may be controlled through at the ends of the block.

An vadvantageous 'feature of the system mits the use of an automatic signal or signals between the ends ol a block when necessary or desirable as where the block is ol' considerable length. These signals have the eiiect of 4giving` space permissive signaling. With theseaut o'matic signals cach of the portions into which the block is divided may be operated as an absolute block or one portion may be operated as an absolute block and the other as a permissive block.

The `various features oi: novelty which characterize my invention are pointed out in theclaims annexed to and forming a part of "this specification. For a better under- @i the drawings: Figures l, and 3 are liacent blocks c quipped with my invention, the form of the invention employed in one block .5 diil'ering slightly from that in the other. i Fig'. 4 is an elevation ol" the case'holding cer- 1 tain of the block instruments at one station. l Fig. 5 is an elevation ol the indicators cml ployed in the case shown in Fig. a.' Fig. 6

l l l. l

-is a diagrammatic representation of one iorin et signal and actuating mechanism proper which may bc' employed, and Fig. Z

l terlocking relays.

Of the two adjacent blocks, AB and BC i shown by Figs. 1, 2 and 3, Fig. l shows one special signals for the sidiiigs, by the operators standing of the invention, however, and the.

. diagrams which, taken together, show two adis an elevation of a portion ol" one ot' the indisclosed is due to the fact that it readily perlOO iio

-station which I have marked station A and most of the track and circuits running from station A to station B. Fig.v 3 similarly shows the apparatusat the remote end of block BC, While' Fig. 7 shows the duplicate set of parts at station B, one set cooperating With those of l to form the complete equipment for block AB and the other set with those shown by Fig. 3 to form the complete equi nient for the block BC.

y It will )e understood of course that the apparatus 'at' stations A and C may or may not be duplicated to cooperate with appa-A ratus at stations more remote from station B to protect other portions of the track than are shown in Figs 1, 2 and 3. The "signale apparatus for the two blocks shown dill'er somewhat though having many features in common. The four sets of stationinstruinents and circuits are in general alike, and

corresponding ones of these and other parts of the apparatus are indicated by the saine this arrangement the followingreadings are obtained at each instrument according to the condition of the block: Block block, At each of the Areference symbols, exponents being ein ployed where necessary to ayoid confusion.

The main rails are divided into sections of suitable length by insulated joints, track relays ZlnZl are connected across the rails one for each section, and each section is provided with a battery ci' other source of signal current IIL-X16. Sidings or branches Dl-D join the main track at various 4points along the two blocks shown. r'idjacent the switch points of each oil the sidings "Lil-Il" is one ol sei. ol contact leones lrllwl, the contacts in each or which are connected to the corresiiionding switch points by a link d so that as the switch points are moved from the normal closed position shown, the contacts are inoyed lroin the 'lull line position shown into the dotted linel position. A short section of each outside siding track rail adjacent the sii-itch points is connected to the 'oppositc'ail oiv the yinai track so that a train on this section of the siding` donergizos the track relay i'or the adjacent inain track section. Y

For each adjacent block end at nach staqtioii there is a ot instruments ivliich is ,duplicated at the other block ends` 'These instruments compris.A km li", In, Il, F5 ,normally spring held in the position shown, but each adapted when deprr ad to be held down by the corre"pending one ol a set ol magnets G1, G2, Gi", G, il the latter be energized; indicator inalfneis Il, l?, l, It, indi-- l' o2.

.is (il,

(y, O", bells oi N3, N4, slot -reney push button, #i Y t, in, andv signal-einiii'olli J1, d'2] is] fr Each oly the ineen/ets Il ivoted arnmure g link' l5, a pivoted indn` Similarly each olv the magri which the magnets I1 and il, hand switch J?, y

Each of the keys F1,

key F1 and push button L1 for station A are y all mounted in a single case A", suitable for mounting on a telegraph table. 'Tha case A is provided -yith upper and .loweriopenings A1 and A2 in front ofthe indicators/il" and I6 different portions of which areexpos'ed' accordingly as magnets il and I1 are enerw gized or are denergizedLthe latter condition being the normal one, which4 is illustrated in Fig. t. Preferablythese targets bear 'legends'v as indicated,v target i the llegend Block, exposed when il is denergized, and the legend Train in, exposed when t1 is energized, while target I'j bears legend Clear, exposed when I1 is energized, and legend Block, ein

posed when magnet I1 is denergized. By

Block clear, Train in block. stations A, B and C there are sources of cur'- rent, as batteries, QA, QB and QC, respectively, and a signaling mechanism proper,

SA, 55B and SC, respectively. mechanism at each block end for controlling train movements into thebiock may comprise a three position signal or two two-position siiials olt any preferred form.

In l. have shown a signal i'neehane isin proper which mayY be used at stat-ion A.

ln this i'icure represents the pivoted threeposition signal blade, S2 the signal rod, Si, r the ointeil links of the electric slot, Sithe armature for holding these links rigid, When slot magnet il* is energized and and S7 links, and S" a bell crank lever connecting the lower end ol,i the slot links to the operatiiig handle 6'". t irow eir- (ollars Slo' and enit controllers Y and F1 res ectivel T when l i Lo the signal blade is nioyeo intothe lo and vertical positions, respectively, these positions corresponding to permissive a'iid fullv clear positions respectively.

` The apparatus shown in Figs. s, and 6 for the right-hand end of block BA may be duplicated at station (l (once) and at station il (tu-ice) for the other block ends. The apparatus shown in F 4 and 5 is simple, emnpact and reliable, and. possesses among other advantages the' important one that ,I while the station instruments through the slot magnets, etc., as We shall sce., eilectually control the signals the parts are not locked iinst increment but may be freely moved at all tinies without likelihood' of injuring the delicate parts` ol the mechanism.

VIn addition to the instruments referred to o e, there are i'nterloeking relays E and lll blocks and BC respectively, and in connection with relay'E1 there are automatic lsignals Y and U, and inconneetion with intermediate switch D1 there is an Yautomatic signal T and circuit control mechan-- ism, the purposes and operation of which willfbe' hereinafter explained indetail.

An understanding o`f the general operation of the signal systemwillbe facilitated by a consideration of thesequence of events occurring when the operatori at Vonestation,

.Say A, desires .to admit a train, moving' toward B, into the-adjacent end of block AB.

yIt should Abe explained that in Vthe drawings the parts are shown with the switches closed, tracks free from trains and signals, at danger. Assuming that 1 block AB is empty and *operator at Jh Wishes to Ladmit a train to block AB, to move toward B, his first step is to communicate his desire to station B, preferably by telephone. If the conditions permit, then operator at A moves hand switch-d J1 toward B and operator at B depresses key. F2, whichis held d'dwn b y inag- 'net G2, energized b current flow froinbatcontacts therein line 13; contacts 1 0() and lOSand line 14 of relay E line 131; contacts controlledby magnet M2; line 123 runningl to B, lnormally closed contacts in box K3, line 12; lcontacts S and 9, closed lby switch J2,

l"normally closed switch Y2, and line i7 to A,ferent from those at E. ,l switch J1, J2, .Por J4 at the station where closed, and theinagnets battery QB. The-current flow through the circuit described in addition to energizing stick `magnet G2 energizes magnet l. and causes it to attract its armature l and shift target I at A so that targets at A'now read from top to bottoinWBlock clear." The energization of magnet l1 also connects lines v19 and 12O, which form part of the energizing A circuitv for slot magnet B1.

The circuit just described forms the absolute signal clearing circuit and a substantially similar circuit must be closed to 'fully .clear the signal at any other b locic end, though in block BC the connections at relay E1 between 'the two lines 13 are slightly dit'- ln each case the signal is to be cleared must be moyed toward the other end of block.

lt will be obvious that the absolute clear circuit cannot be completed unless the two hand switches J1 J2 are in the positions described, and the switches D1, D2 and D3 are M3 and M1 of interlocking relay E ai'e energized, and that if the circuit is establishedv it will bebroken on any chan e in these elements. i Furthermore the signa SB, at B -for block AB must 'be at danarmature of magnet O1 when thelatter is de-,

placed by :latein ger or switch y2 will be open. Magnets M3 and M1 will not both be energized unless block AB is free frein trains as will be explained. .It is apparent also that operators at A and B cannot now proceed to eftablish the absolute clear circuit lor B without breaking fthe absolute clear circuit for A, sincev at each station the circuit breaker H1 or H2 and hand switch J1 or J2 must be each in one position to clearI the signal at one station and in another position to clear the signal at the-other station.

The operation of `the signal Sii at station A requires the energization of slot magnet B1. R1 is energized by battery QA through the `following circuit: lines 17, i8, 19, armalure I; lilies' 20, 21, normally closed contact 14W, line 22, circuit breaker h1, line 23, upper energized; lines 24- and 3, and battery .Is Magnet O1 is normally energized by a circuit which includes the winding ofniagnet O1 battery Q armatures of traclifrelays Z1and Z2 and lines '25. rlhis circuit is broken by denergization of track relays Z1 or Z2, when ai) a train in either of thetrack sections toA .which they are connected. This arrangeinent results in preventing the signal at L frein being cleared until a train arrives at tracl; section to which relay Z1 belongs, thus 95 preyentiiic; the signal operators frein anticipating tiain `movements and clearing the. signals lie-ore such clearance is necessary.

The presence of a train in sections to which rel-ay Z1 and are connectedI isindi- 10c cated by an electric bell or other annunciator N1 energized when magnet G1 is denergized, through battery OA and lines 26, lower armature of magnet O1, lines 27, 24 and 3. The length oi the annunciator sections is optional with the user* The operation of eneigizing slot inagiiiets R2, lB-or R1 is substantially siinilar to that for ll1'thouglrthe circuit arrangements are slight-ly different. ln the case of each oi' 110 slot inaginits R2, R3 and R1 there is no circuit controller VW and'lines- 2l and 22 arci relines Z1 running 'from line 2U to corresponding circuit breaker 7b2, 7151 or .751. The control of the encrgizatioi'i of magnet O1 115 by relays Z1 and. Z and battery Q11 is through circuit arrangements exactly like those' for magnet U1. Magnet O11 is controlled `by trachr relays Zb'vaud Z7 through a circuit including these arniz'tturcs, line "25, i2() line 3] and battery Q lo line i., line 'l yto junction of line 2, and line 'l5 vto magnet O and' back, to arniature of relay Z". Magnet O2 is con/trolled by track relays Z1), Z1" and Z11, line l5 running from varmature of relay 125 Z10 to armature of relay M5, the energtizntion of which depends on Z11as willA be exlfilained Current for ei'iergiz/,ing magnet G2 battery Q8 atl?, one terniinal beiiigconnectcd to line 25 furnished by of the `battery i 30 'box A0 to be actuated by key d other end ofthe block 'from `\being cleared,

regardless of the otherircuit conditions. As'soon as the train entering the block AB at A, cornes on track section to which relay Z3 is connected,magnet M3 oi interlocking rclay E is deenergized, as the armature of relay Z3 aswell as the armatures ol`relays Z1 and.

Z5 Aare included in the energizing circuit oi"lv 'rela M3. This circuit includes-1n addition tot ese relay armatures the following: battery Q1, lines 31, 30, 29 and 28 to line 1, to

?O which one terminal of battery Q1'is connected. When magnet M3 is denergized and armature 100 drops, the absolute clear circuit for signal SA is broken and magnets I1 and G2 are both deenergized.` This breaks circuit for, .magnet RPand returns .signal SA to danger-,land by allowing'key F2 'to resume`l its normal position, Botines-operator at B.

that train has entered block at A. A bell may be arranged either within or Without the F2 When released. f y l While signal'SA cannot be fully cleared again so long as'the train is in the block, it

- can be moved into the cautionary orpermissive position as soon as a train entering at A 1 has passed beyond the track section towhlch` relay Z3 is connected. To establish the permissive signal clearing circuit operatorat A communicates with operator at B and the 40 latter, if willing? again depresses his key F Operator at A must also throw` sv-.fitch J1 to the right of normal. The following circuit is then established: battery QB line 3, L2, key F2, line 2, line 1, line 4 at A, line 5 including switch P1 and magnet t1, contacts 11 and-10 and switch J 1, line 37, normally closed contact in box K1, line 36, armature of relay Z3, line 35, 'interlocking armatures 101 and 105 of E Which are now in contact and .from

.50 thence back to battery QB through lines 131,

13, 12 and 17,v and suitches, etc., as in the' case of tlievabsolute'clerar circuit. The energization or' magnet i1 shifts target i so that the target reading at A is now Train in block.

lwhen magnet i1 is energized its' armature connects lines 19 and20. 'lhis permits niagynet R1'to be energized ainlsignal SA to he cleared, as in the case of the absolute clear circuit, before described. 1n this caso, however the signal SA can only he moved to the cautionary position since further movement of the signal opens switch P1. .iffhen the, train nonv enters the block and moves .by signal SA onto track section to which??1 is connected, signal SA again goes to danger.

Assoon as relay Z3 is again energized the sig- -1 is to e noted that in all cases the movement andthe signal cannot again be cleared either absolutely or permissiyely, except by the co eration of the operators at the two ends of t e block.

Magnet M* of relay E is energized' by battery Q6' through a circuit analogous to that for energizing magnet M3, the only material difference bein that in the case of magnet M? one termina of the magnet runs directly to the armatureof relay Z5, While inv the case of magnetM1. a conductor 291 runs fromar mature of relay Z6 vto one contact in switch box K2, the corresponding-contact being connected to oneterminal or' magnet M1. vConductor 291 includes Winding of-ma'gnet M1,

the purpose of which Will be explained later..

As soon asa trainmovin fromA toward B enterssection to which re ay Z*1 is connected, the latter is denergized and thus o ens the circuit through-M1. Since magnet i 3 is already denergized, however, armatures 104 and lolvmechanicallyinterlock and the latter is held by the former in engagement with .armature 1 05, until magnet M4 is. again energized, regardless' of Whether magnet M3 is energized or not. In consequence, the permissive circuit for signal SA can be, established regardless of thenumberl or'location of trains -in block VAB moving toward B, rovided only that relay Z? is energized.` he purpose of the emergency push button circuit reakers L1, L?, L3 and L4 is to permit an' operator Who 'has previously actuated his operating key F1, F?, F3 or F1, as the case may be, to close the signal circuit permitting the clearance oi' a signal at the opposite end of a block from that at which the operator is located, to break the signal circuit closed, in case of'emergency, by actuating the one of the push button devices L1, L2, L? or L11 located at his station.

T he control oi train movements fron) B vte Awis the same as in the opposite direction, except as already indicated.

T he operation of block BC generally like that block AB, except as it is modified by the provisions had for the control of train movements througljL automaticsigna-ls V and U. These provisions do not a'liect the operation o1PY the main signals at the endkoi' the block when the absoluto or permisrgiwz signal clearing uits are established, nor do they a'h'oct ii.- slalh hment of the absolute sig* nalilenring cil uits, but theydo ail'ect tl establisluneut oi' the permissive signal cle ing rirruits. in the arrarU'onun. shown ier block B," 'the permissive mi 'er ing circuit Yl'or signal Si or SC cannot be established 4maybe established, assuming that oper` The magnet M of interlocking relay BC is.

energized bybatteryQE through a circuit including a portionof line 43 and:` oneiarmature of relay M5 and a portion of line 112.

.larly, magnet M7 is energized from battery Q5 by a circuit including a portion ofrliiie 42 line 43 and armature of relay M5. "Signals U .andV are also energized batteries Q8l and 5, respectively, through circuits comprising lines 42 and contacts controlled .by the enerization of magnets M5 and M5 res ectivelv.4 .g s y; MagnetM5l is energized when track relays Z12 Z545 and Z1.4 are energized bv circuit inchiding in addition to-v ltlie armatures of these relays,'battcry Q5, lines and a ortion of line 1. Magnet M5 is energized rom battery Q7 through a similar circuit controlled by track relays Z5, Zl0

When a train enters one end ol-block BC,

for instance at C, magnet M5 is at once deenergized and remainsin this condition until I of magnet M5, in addition to denergizing magnet M7, causes normally clear signal4 V to fallfinto the danger or cautionary position, either being optional with the user. 5

When magnet M7 is denergi'zed, contact 107 engagesA contact 11,1and as .contacts 107 and 110 interlock, when magnets Mq1 and M are denergized, contacts 107 and 111 `remain in engagement until the-train moving from B" to C has passed out of the block. Vi/ith contacts i107 and A111 in engagementand magnet M7 energized, the following permissive signal -clearing circuits for signal SC ators at B and C cooperate as described for 'block AB; Battery'QB, line 3', L3 F5, lilies .2, 1, 1 at C, Hf, lines 5 through switch l)4 and winding oi magnet t4, contacts 11 and 10'and switch J4, line 37, normally closed contacts in box K5, line 36, contacts 106 and 111, line 135,coiitacts controlled by magnet Mlinr' 13, normally closedv contacts in boX K4, line 12, contacts-8 and 9 and switch J5, vand line 17 fto battery QB. This circuit may be established whenever the block is unoccupied between El and (l, regardless of the presence of a train or trains moving toward B in. ythe block portion between E and C. Signal'U is at clear or danger position accordingly as the block portion #last inentioned. is occupied or not, and this signal determines accordingly whether or not a train.

arriving at El froniC may proceed freely or with caution' through the remainder of the block. The train vmovements troni B to C are controlled. in the saine manner as movements from C to B.

In the case ot' each of the switches D1, D2, D5, DJL and D5 the opening of the switchcauses certain changes inthe contacts or clectrical switches located in the corresponding one ot' switch boxes 1&1, h2, K, Kf and K5. j In the case vof switches D" and D5 the opening of the switches causes the normally l opencontactsin the switch box 1U and K5 to close low resistance shunts 60 across the Vrails of Athe track sections to which the track relays Z5 and ZM are connected, so that those relays are denergized and when switches are opened. This produces the saine etl'ect Iupon the automatic lsignals and interlocking relays E1 that would be produced by the cntrance of a train oiito these track sections. lVlo'i'eover, since both the permissive and absolute V clearing circuits are broken at the boxes K and l5when the corresponding switches D4 and D5.are operated, main signals at the end of the block cannotbe .moved out of the danger position until the switches are again closed, 'and if these signals are clear when the switch is open the breaking of these circuits immediately returns the signals to danger. The presence ot a train on a switch portion connected to the track circuit proper by bond d" of course has the vsaine eil'ect. upon the signal circuits as the presence of a train on the track section to which the bond dl runs. in consequence of thisl arrangement a train .moving onto the niaiii track from siding D" or`D5 prevents the clearancegof any signal until after the train moving .toward B or- C respectively liasleft the block,` or moving toward C or B respec- |tively, has passed beyond the corresponding automatic signal at E54. Similarly 'the prs--A ence of a train on the section of switch D5 .connected to the adjacent track section by' bond d5 makes it impossible to give a signal at eitherend of the station until the train has ypassed beyond relay Z going toward A or until after it has passed out ol the block at B when going toward C. ln thecase of switches in block AB, the shunts 60 are obviously not needed. In the case ot switches D3, DA1 and l 5 train crews are instructed not to leave the siding until permission has been received from the adjacent signal operator who gives the permission only after consulting the other operator. given preferably by telephone. .For intermediate switches in block A-B, that is, for sidings or brai'iches joining the main track at points between the track sections to which relays Z5 and Zs are connected, c. fit points where the'piesence of a train does not prevent tlie giving ol' a cautionary indication by the appropriate niain signal, means should be provided for obtaining better protection than is had at switches D5, D4 and D5. One of the arrangements which I propose to einploy is shown in block AB for switch D?.

'lhis permission is tacts controlled by armature of M2, line 43,

contact in box K2 land a portion of line 291 back to battery lt will thus be seen that so long as switch D2 is closed, magnet M2Will be energized from its battery regardless of Whether or not the circuit through magnet M4` is maintained. Permission to open the switch is given the crew et' the train on the siding by the operator at B, if the train is to .move toward B and by the operator at A, if.

the train 'is to move toward A, after a conference between the two operators" in either case. When the switch D2 is opened, the relay M2, as Well as magnet M4 is denergized by the breaking of the cii'cuit inbox K2. rThe deiiergization of magnet M2 breaks the absolute and permissive signal clearing circuits ing of thesvvitch returns it to danger.

through the consequent movement of the ar- 'matures connecting lines 3 and 131 and ever,4 the train moves toward i lines 35 and 351. This prevents signals at A and B trom being cleared absolutely or permissively and it one of these is clear the 'open- So long as the train moving out of the siding D2 isb'etvveen B and E magnet M4 remains deenergized and consequently relay M2 does also. The result ot this is that if the train coming out of the siding moves toward B, no signal at the end of -tlie block can be cleared until the train leaves the block. lf, howl i, a caution ary signal'indication can be given at B in the usual manner, as soon'as t-lie train iiiovfe'c'll' `the track section to which track relay Z is connected, provided, el.l course, that switch D2 is closed.

lith the switch or siding D1 there 1s provided an automatic three-position dwarf signal T by means of which the cre* of a train on the siding 'D1 may-be informed that the block from' A to B is free to them and is clear, so

lthat they may enter the block, but that the "latter is occupied by a tram moving` trom A toward B.

The dwarf signal T is electrically interlocked with the signal SA at i'i so that Ionly One of these signals may be cleared at a time and the-.clearance oi the signal T requires the cooperation oi the signal oixierators at stations A. 'and B.

The signal T comprises an electrical actu- `ating device which sets the si nal to the full clear osition i Yhen current new through tl ie signa between lines 4T and .Si is .had and to the permissive position ii'hen the current oW through the signal is between lines 57 and 47. Normally closed contact W2 and normally open contacts XV and N1 are connected to siidtch D1, sothat when the latter is opened contact v l2 is opened and contacts W and N -1 are closed.

Vl/'hen the operator attl becomes aware that a train on the siding at D1 ivislies to enter the mainv track and proceed toward B, the operator at i confers with the operator at B and in case permission'for the moveJ ment is given the operator-.at A then notilies the crew ofthe siding` train .to open the switch D1. This opens the normally closed contacts in switch boX K1 and Closes thenormally opened contacts in the' box'. tfalso opens normally closed Contact 5W thus preventing completion of the energizing circuit ior the slot magnetulii and closes normally open eontacts WV and W1. Operator at .fi

then notities the operator at B that the 'train' on the siding is ready to move and thelatter then depresses key F2. This establishes a signal clearing circuit 'which ii" the block isl free from trams is like the absolute signal 2 clearing circuit 4.previously described 'for block AB, With'the exceptiorrthat the circui instead of leading directly through' the boX -K1 iromthe line 13, continues through line 45, contact controlled by relay Z3, line 451 to contact normally open (but noiv closed) in box K1, thence through line de. and Winding of magnet M, line 46 and line l? to line l and thence back to battery QB.

The energization oi" winding M does two things: lt causes signal T to go to the full clear position and it energizes the indicator magnet l1 at station A.' The circuit which signal T cleared is as follows: battery Q2, line 4S, contacts controlled by mag net M, line 49, contacts controlled by deiiergized magnet M1, lines 5() and il?, actuating coil for signal. T and line to battery.

The circuit by which magnet l1 is ener.-

gized is as follows: Battery 2, lines 48, up-

per contacts 'controlled by magnet El, line 49, contacts controlled by niagiietM1, lines 50, el?, l and ll, contact breaker H1, lines and 6 ing winding-r of magnet l1,y contacts 7 f? 2, contact l?, linee and 54 back to batt f The energization 'of magnet. l hitte thel indicator i sol-that the instruments at A now read Block clear 7 and this i' "l'cation serves to inform theoperator f that the s' ial T has been cleared.

l:ut of the siding and re- 'tlie various circuits just 1i broken and the dwarf signal normal position, the latter notiying the operator at e. that the train on tlie'siding has accepted the signal. After this train so i. y .anger and the indicator con? trolled by the magnet l1 drops back .to itsv li .1" which must be to the left, A

iis

Y elast? moves that the track relay Z3 is again energized', a train may be admitted to the block by signal SA with caution signal as before described, or a'train on the siding D1 may be admitted to the,block with a caution indication by dwarf signal T. In either case' the cooperation of the two operators at A and B is recpiircd;y B to depress key F2, and A to threw switch J1 to the lett.

The Circuit by which the dwarf signal T :battery QB. When magnet M1 is energized in the manner above ifescribed, it, in turn, causes the three-position signal T to come to the 'cautionary position 'and also energizcs indicator'inagnet. The circuit by which the signal T is set to the intermediate position isas followst' Battery Q2, lines 4S and 5.3,

\ lower contact of magnet hl and lines 56 and 57 signal T, lines e7 'and-50 contact of inagnet M1, and lines 5 8 and 5,4 fback to battery Q2 gized, when magnet M1 is energized, is as tpllows: Battery Q?, lines 4S and 55, lower contact ,et magnet M, line 56, contact-Vi, lines 59 and 37,*contacts 10 and 11, switch J1 (the latter being to the right) line 5, including switch P1, and winding of magnet i1, circuit breakerH1, line 4, line l .to the junction with line 47 3 lines 47 and 50, contacts of armature `M1, line 58 back to battery Q2, After signal T has thus been set in the permissive position thetrain moving trein sidingI D1 into the block'. denergizes relay Z`9l and this restores .vided other conditions permit.`

l thc signal 'T to danger and also returns the indicator connected to armature ot magnet i1 to the normal position. After switch D1 has been closed the signal circuits are then in the usual condition in whichit is possible to adl mit a train` by signal T or by signal SA intoI the block AB with a cautionary -signal pro- TvYith the system, disclosed it ,Vliorrn` 19 train. orders 4only when train While'in accordance with the requirements of the statutes I have shown and described in detail the best forms et my invention now known.to me, it will bc understood by those skilled in the artthat many changes maybe ,made rornkthe forms disclosed without departing from the spirit ofthe invention and The circuit byivhic'h magnet i1 is eneris possible to eliminate Form 3l train ,orders anduse that certain features of invention disclosed herein inayfbeuseiliii sedici-cases without a corresponding use 'nfother features ofthe system disclose-tti Having now described my invention, what/ l claim as new and desire to secure by Letters Patent is: i

1. -Inl ablock signal systemen electrically controlled manually operated signal and opeiating mechanism therefor including a slot i circuit and means `preventingthe energize,- tion of said circuit exce it when a portion of the track at one side of t-ie`signal is free from trains anda portion of track at the other side of' the signal is occupied by a train.

2. In an electrically controlled block signal system for single track railways, thecombination ofsignals'which may be clearedabsolutely oi" permissively, located one at each end et a block, devices responsive to thel presence and location of a train or trains in the block, means for clearing cach of said signals, the clearing means foreach signal being governed parts at the two ends of the block, which must be'manually actuated for every clearance either absolute oi' permissive of the signal, and means actuated by the entrance of a by said devices and including' train into the block at either eiid'tor returning the corresponding signal to danger.

A block signal system for single track railways comprising the combinationof a circuit closing key, a magnet serving when en'- ergized to hold said key iii the circuit closing position, a three-position switch, and an elecf trically controlled signal mechanism at each end of a block, circuit closing devices responsive tol thc presence of a train or `trains in the block, and circuit connections where' ,bv when bothof said switches are set in pre-v determined positions and one only of said keys is moved linto the circuit closing posi-` tion and said block is tree from trains, a circuit is established whichfcnergizes the magnet toi" holding said one key and permits the signal mechanism4 at the opposite end of the block to be operated. l Ll, Ablo'ck signal system for single track railways, comprising in combination an elec-' trically controlled signal inechanisn'i includ'- ing a slot-circuit at'cach end of a bl ck, and means responsive tothe presencele atrai'n on a track portion withoutsaid'blockbut adjacent one end thereof, for preventing the closuri-i of the slot circuit of the signal mechanism at that block end, except when saidl track portion occupied by'a train. f

5. A block signal system for single track iio iis

railways,,comprising in combination an`.elec

trically controlled signal mechanism including a slot circuit at each end of a b1ock,'mean s responsive to the presence of a train von. a

cent one end thereotor preventing the c osure of the slot circuit of the signal mechanism at that block end, except When said track portion is occupied by atrain, and

means for indicating at the adjacent block end the presence of a train on said track portin.

, 6. In a-block signal system'the combina- 'other end for interrupting said circuit.

7. A blocksignal. system for single track railways comprising the combination at' each end of a block of a .normally open circuit closing key, a magnet serving When energized and after said key is closed to hold the latter'closed, a threeposition switch and an electrically controlled manually actuated signal, circuit closing devices" responsive to the presence, locationand direction of movement of a train in said block, and circuit connections so arranged that when the key' at one end *of the block is closedand ,the switches at the two block ends are set in predetermined positions', the signal ai the other end of the block may be cleared absolutely or permissively depending on the condition.

of said devices.

' 8. A block signal system for single track1 railways, comprising the 4combination ofa cirlc'uit closing key normally in the'open circuit position, a magnet by which said key after being closed may be held closed, a

three-position switch andan electrically-controlled signal mechanism at each end lof a block, circuit closing devices responsive to the presence, location and direction of movement of a train in said block, and circuit convnections whereby When the circuit closing key at one end of said block` is moved into the circuit closing position and the three-position switches at the tvro ends ci the block are set in predetermined positions the magnet fmaintaining the closure of' the closed key is -,1iei"gized and the signal mechanism at the other ond oi the block from said/closed key may be cleared absolutely' accordingly when the block is free from,Lv trains or perniissivcly xi'hen the portion of the block immediately` adjacent said other block end is rco from trains, and the trains in theI block navoentercd at said other block cud.

0 in block signal systen'i for single track ,f railways the combination with the main y track between the stations at the end of a block and siding joining the main track adjacent one of said stations, of main signal mechanisms 'adapted to give clear andper-v i missive indications located one at each station, and a signal mechanism 'for said siding I also adapted to give clear and permissive in- I dications, circuit closing devices responsive to the presence of a train or trains in difierent -portions of the 'track and circuit connec- .tions controlled' thereby and by the signal 1 operators at the ends ofthe block, governing i the signal indications of all oi said signals and arranged to prevent more than" one of i said signals from being cleared at a time. .10. in a block signal system, a block sigl nal instrument comprising acase having a pair oi openings formed in one side in juxtaposition to each other,'a two-position indicator back of each opening, an electro-magnetic `device for each indicatorl arranged When energized to move the corresponding indicator from one position'to the other and means for energizing one' of said electro-magnetic devices when a permissive lsignal indication is to be had and the other of said elecdication is proper.

1l. In a block signalsystem, a block signal instrument comprising a case having a pair of openings formed in one side in iuxtaposi-tion to each other, a two-position indicas tor back of each opening, an electro-magnetic device for each indicator, arranged indicator from one of said positions to the other and means for energizing onef said electro-magnetic -devices when a permissive signal indication may be had and the other {'of said electro-magnetic devices when a clear signal indication is `roper, each of said indil cators bearing two egends, one or the'. other of Which is exposed through thecorresponding casing opening accordingly as the indicator is in one or the other off its positions, and the legends on the'4 two indicators eX- posed at'one time bein arranged to jointly indicate the condition oi the block. V

l2. In a block signal system for single track railways, an interlocking relay includ; ing a'pair of magnets for each block, means for denergizing one of the magnets of said relay when the portionoi' a block 'adjacent one end is occupied by a train and for deenergizing the o'ther magnetoi the relay when a portion of the block adjacent the other end is occupied, a. signal at each end ofthe block, means dependent upon the energization of i both magnets of said relay for establishing absolute signal clearingcircuits for said signals, and me'ans dependent upon said relay i 'for establishing a permissive signal ciearing circuit,whenv one or both magnets of d relay are deenergized for the signal at the end oi the block corresponding to the one inagnet of theyrelay, 'or the iirst magnet of the i relay denergizcd. Y .f i 13. In a block signal 'system for single when energized to move thecorresponding tre-magnetic devices when a clear. signal intrack railways a siding joining the main track at a'pointwitlnn a block and adjacent one end thereof, a signal at said block end, a signal at the siding, means governed by the permitsaid slot circuit to be energized when either of said magnets is energized, and conf tacts operated by the opening of said siding to the main track for causing the siding sig-'g nal to be cleared absolutely or permissively when said signal clearing circuits are established, and for preventing the slot fcircuit for f t i magnets energized when the block 1s tree 1 from trains', and one .denergized when one the main signa rom being established.

14. In a block signal system for single track railways the Acombination with `the.

main track between the stations at the lends l of the block and a siding joining the main track between the stations, of devices responsive to the presence ot a train or trains in the block, a signal at each block end, means operated jointly by the operatorsat the two stations and controlled by said devices by. which each signal may be cleared absolutely or ermissively under different conditions, an ated by the opening of said switch for preventing either of said signals from being cleared while the switch is opened and for returning either ot the signals to danger if the latter 1s cleared when the switch is opened.

15. In a block signal system for single track railways the combination ot a manually controlled signal at each end of a block, an automatic signal between the ends of the means automatically actu- Y block, devices responsive to the presence ot 'a train or trams 1n the block, cncult conne'ctions, and operating means at'the two ends ot the block whereby the clearance ot either conditions existing in said block for estabz lishing absolute and permissive signal clearl ing circuits for said signals, a slot circuitor l the main signal, and a pair ot magnets one. energized when an absolute clearing circuit is i established and the other when a permissive clearing circuit is established, contacts controlled by said magnets normally serving toA signal either absolutely or permissively requires the coperation of the operators at the two ends of the block and whereby saidI automatic signal indicates to a train moving from one end of the blockl to the other whether or not the portion of the track between'said automatic signal and the-far end ot the block is occupied by a train or trains.

16. ln .a block signal system for single track railways, the combination with signals at the eiids ot' a block, of means by which said signals may be cleared absolutely or permissively depending on thevcondition of the block between the signals, said means including an interlocking relay, comprising a pair of portionot the block, and the other denergized when another` portion of the block, is

occupied by train or trains, and armatures,

one for each ot said magnets, which interlock when both magnets are denergized to p revent the armature of 'the magnet iirst deencrgized from returning to its normal position until after the magnet last denergized isagain energized, and to prevent the" armature of the. magnet last denergized from moving, when such magnet is denergized,

into the `posltion 1n which it would move if the other magnet were energized at that time, and circuit controlling devices operated by the movements of said armatures.

GEORGE PFLASTERER Witnesses W. S. LYNCH, H. W. FORMAN.

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