264

Rock Island Developes Single-Track Station-

Based on Coded Track

Arrangement of signals and controls make possible automatic signal protec­ tion on a very long mileage at a cost justified by increased safety protec­ tion on a line handling fast trains but a comparatively few such trains

Above-Train pass­ ing single - distant si g nal l ocatio n . Right-Train a t passing-track Ioca­ rion, showing- sta­ t ion -e nt e r ­ ing signal and sta­ tion-leaving signal

ON the Rocky Mountain Route of the country. Except for breaks in daily between Belleville, Kan., and Chicago, Rock Island & Pacific, be­ grade near rivers, the line rises gradu­ Goodland, Colo., 234 miles, as well as tween Chicago and Denver or Colo­ ally westward, the elevation above sea a local passenger train daily except rado Springs, there is 490 miles of level being 1,035 ft. at Omaha and Sunday between Jansen, Neb., and single track between Omaha, Neb., 5,359 ft. at Limon. F rom Limon, Rock Fairbury, 6 miles. and Limon, Colo., which is being Island trains operate over the Union equipped with an automatic block sig­ Pacific for 90 miles to Denver. The Freight Service naling system that includes several Rock Island main line extends 79 new and novel features, not only with miles from Limon to Colorado The fast through fr eight service reference to the operation and spacing Springs. During recent years the scheduled daily includes two trains in of trains, but also in the use of a new track has been improved to permit each direction 'between Omaha and and unique application of coded track higher train speeds.Lightweight high­ Limon in addition to local mixed circuits by means of which the signal­ speed passenger trains, the Rocky trains on certain subdivisions. Extra ing controls require no line wires in Mountain Rockets, are operated each trains are operated as required. Thus, the station -to-station blocks. T he ter­ way daily on fast through schedules. on some sections, as for example be­ ritory involved is shown in the accom­ In addition to a second through pas­ tween Fairbury and Goodland, the panying map, Fig. 1. senger train in each direction daily, schedules include six passenger trains Between Omaha and Limon the using standard equipment, there is and fr om four to six frei ght trains Rock Island traverses rolling prairie also a local passenger train each way totaling ten to twelve trains. On other 265 a Unique System of to-Station A utomatic Block

Circuits Without Line Wires

subdivisions the total may be eight to the volume of traffi c and funds avail­ ten trains daily. H eretofore there was able for signaling on this line. no automatic block signal protection on this terri tory except in a few iso­ Protection and Track Capacity lated locations for protection on of the N ew Signaling curves and over switches. and, there­ fore, the primary need was for an Thi s new signaling on the Rock automatic block system to includ e Island pro vides the same safety pro­ complete track circuits for protection tection as any other automatic signal­ again st collisions as well as to check ing, including protection from colli­ for broken rails and the position of sions, broken rails and misplaced switches in the entire terr itory. On switches. The installation includes account of the extended mileage, 490 separate automatic blocks through the miles, between Omaha and Limon, limits of the stations. the same as in the character of the line, and the com­ conventional signaling. F or example paratively light volume of traffic, only at station A in Fig. 2, signal 9 is the a limited expenditur e could be author­ westwa rd station-entering signal, and ized for the desired signal protection. signal 10 is the eastward station-en­ In this instance necessity was the tering signal. In orde r to give an en­ mother of invention. The Rock Island gineman advance inf ormation con­ signal engineer and his staff planned a cern ing the aspect displayed by a sta­ continuous track circuit controlled tion-e ntering signal, there is a distan t system with blocks extending from signal located at full braking distance station to station. plus medium-speed braking distance f rom each station-entering signal. For No Intermediate Blocks example in Fig. 2, signals 7 and 12 are the distant signals for station -enter ing East of F airbury no intermediate signals 9 and 10, respectively, and sig­ automatic blocks as such ar e provided nals 6 and 1 are the distan ce signals to permit trains to follow one another for station-enterting signals 4 and 3, in a station-to-station block. Vi est of respectively. An important point is Fairbury, however, the signal system that signals such as 1, 6, 7 and 12 are has been further developed and ex­ merely distant signals and they are not tended to prov ide addi tional signals in located or controlled as intermediate the center of certain station-to- stati on automatic signals. Single-distant signal location show­ blocks in excess of eight miles in ord er ing instrument case and battery bo x to permit trains to follow each other. Station-to-Station Block Thi s featu re is accomplished without Is Something Di fferent the use of line wires, and the signal project, when an eastbound tr ain de­ layout is similar to that at a passing In this Rock Island project the sta­ parts from station A, the eastward tr ack locat ion, but minu s the passing tion-leaving signals and their controls station-leaving signal 8 at this siding track. are different from conventional prac­ will continue to display the Stop as­ Furthermore, the Rock I sland sig­ tice in that the block is from siding to pect to hold a following eastward nal staff devised a new and novel siding, so that following trains are us­ tra in until the leading train has passed scheme of using coded track circuits ually spaced the full station-to-station beyond station B or has entered the to cont rol single-track autom atic block distance rather than being spaced by siding at that stati on. signaling without line control circuits inter mediate automatic signals, with On this territory of the Rock Is­ in the station-to-stat ion blocks. As the excep tion of certain instances west land, following tr ains of the same compared with conventional signaling of Fairb ury, mentioned heretofore, class and speed ar e not ord inari ly op­ the use of station-to-station blocks re­ where intermediates have been in­ erated very close together, and, there­ duced the number of signals required, stalled in station-to-station blocks fore, the spacing from stat ion to sta­ and the new circuit scheme eliminated longer than eight miles to allow for tion does not cause tr ain delays on this line wires and pole line work so that following train movements. Ref erring score. Where a fr eight train is on a the cost of the installation is consid­ to F ig. 2, which illustrates a station­ siding waiting for a passenger train ered to be in proper relationship with to-station block in the Rock I sland of the same direction to pass, the 266 RAILWA Y SI GNALING Apr il, 1946 freight will have to wait at station A, With an eastbound train passing from additi on the yellow is an Approach for example, until the passenger train station A 'to station B, signal 12 re­ aspect indicating that signal 9 is dis­ goes beyond station B. O n account of main s at Stop until the train has playing red. Also signal 7 displays the few instances of thi s nature due passed signal 8, af ter which signal green to indicate that signal 9 is dis­ to the compa ratively small total num­ 10 displays Approach, and signal 12 playing yellow or green, and that the ber of trains, and because the high clears to allow a second train to fol­ tr ack is unoccupied between signal 7 speed of passenger trains reduces the low. Signal 8 will not clear until the and signal 11. time to pass beyond the next station, first tr ain is by signal 4 and signal 6 the delays due to the station-to-statio n is displaying Approach. Impulses Feed Both Directions, Ar e blocks are few and of short duration. Co-ordinated to Prevent Interfer­ These delays are recognized as neces­ Aspects Displayed ence, but Are Not Interdependent sar y in the system based on the sta­ tion-to-stat ion block, which in turn In F ig. 2, station-leaving signals In a station-to-station block, as for was accepted in order to reduce the such as signal 8 at station A and signal example between signal 8 at the sta­ costs to be in conformity with funds 5 at station B are absolute signals to tion A and signal 5 at station B, the which could be justified and author­ which R ule 292 app lies. Such signals signals are controlled by a new and ized. Based on observa tions since long are normal-clear signals. In view of unique adaptation of tr ack circuits, sections of the signaling system have the fact that these are station-to-sta­ without the use of line circuits. T he been placed in service, the trains leave tion signals, they display only two as­ commonly accepted term coded tr ack stations on green aspects, thus accel- pects, red for Stop and green for Pro- circuits does not exac tly apply to this

------r-'-KAN'-S AS'-'- COLORADO I i~l l ToDenverts> t:: 0, c ...... c: § c6 et ~ 0'" tip .§ ~ Fig. 1 Map of the territory be- . ~ - R.I. -"To Colorado Spn'ng s new scheme because different rates of code, such as 75 or 180 per minute, are not used to control signals to dis­ ceed. No yellow aspect is provided on play different aspects. In order to ex­ this signal because it is not controlled plain the Rock Island scheme, the erating to maximum authorized speed or located to display an Ap proach as­ term impulse may well be used. The promptly, whereas in a different sys­ pect for any signal ahead. absolute station-leaving signals, such tem in which a train would depart on Station-entering signals such as sig­ as signalS and signal 8, are capable of a yellow aspect, the train would be re­ nals 10 and 9 at station A ar e normal­ displaying only two aspects. When no quired to proceed at reduced speed un­ danger permi ssive signals to which track circuit ener gy impulses are being til arriving at a signal displaying a Rule 291 applies. Such signals are received at such a signal, it displays more favorable aspect. T herefore, the capable of displaying three aspects, Stop, but when impulses ar e being re­ experience of the Rock Island is that green, yellow and red. The green as­ ceived, the signal displays green. tr ain delays have proven nil because pect indicates that the block on the As shown in the typical diagr am, of the use of green aspects . main track between this signal 9 and F ig. 4, the track circuits on this Rock

Fig. 2- Typ ical station-to-station track and signal layout with no intermediate signals as such

W here interm ediate signals for II is unoccupied and also that s ignal Island signaling are the double-end each direction are provided in station­ 11 is displaying a green aspect. The type, i.e., there is both a relay and a to-station blocks in excess of eight yellow on station-entering signal 9 is batt ery at both ends of every track miles, each signal is provided with a an Approach aspect to indicate that circuit. W ith the system dormant, the distant signal, similar to the arra nge­ signal 11 is displaying the red aspect. relay is connected. But if the track ment at passing track locations, form ­ The distant signal. such as signal 7, circuit is to be fed from a given end, ing in reality, two station-to-station is a normal-danger permissive signal the contacts ar e operated to connect blocks witho ut a passing track at one. to which Rule 291 app lies. I t is capa­ the battery rather than the relay. T his arrangement is shown in F ig. 3, ble of displaying three aspects. Red Thus the track circuits can be fed and with the addi tional signals 7, 8, 9 and indicates Stop and then P roceed. The operated in either one direction or the 10, signals 7 and 10 being distant sig­ yellow and gre en aspects are track cir­ other. Looking at it another way, they nals to signals 9 and 8, respectively. cuit controlled up to signal 9, and in can be fed first one way and then the April, 1946 RAILWA Y SIGN A LI N G 267 other through a station-to-station relay at the east end of track circuit e be of sufficient duration to allow time block as a whole. There is nothing is picked up and then released. While for these operations through all the new about this either-direction double­ this relay is up a surge of energy is track circuits going east, and in addi­ end track circuit, the principle having fed to the coil 'of a slow-release relay, tion the same duration for the west- been used in the Rock Island's Blue and as long as the track relay is oper­ Island-Silvis terr itory for several ated not less than a certain number of years, as well as on numerous other times per minute so that the slow-re­ roads. lease relay gets shots at the rat e of not The new feature on the Rock Island less than the certain number of times is that as applying to the control of station- leaving signals, such as signal 8 and 5, the track circuits for the sta-

NEB RASKA

c c .... C '"c; C> '" .,e> co C ...... c -0 '" c 0 "~ c c 0 -cc ts ts '" '" e C> "C C V) 'is .s ] -0 ward pulses to feed through the entire ~ ." -<: -0 '" ...... t: -1" ~ '" "'- v CO) -; ... V)E C1 station-to-station block. -c '"'- ~~ "t "" -" t; Q '" An important point is that the send­ ing of a westward impulse from sig­ per minute, the slow-release relay nal 5 does not depend on the receipt tween Omaha, Neb., and Limon, Colo. stays up, thu s effecting controls to dis­ of an eastward impulse at that loca­ play the green aspect in signal S, tion. T he eastward pulse must simply tion-to-station block are normally in In this scheme an eastward impulse get there when it should, otherwise it operation in both directions to hold goes through the track circuits of the will be opposing a westward impulse both such signals at the green aspect, entire station-to-station block which in which would cause unsatisfactory op-

Fig. 3- Track and signal layout for station-to-station bl ocks in excess of eight miles, showing additional signals

Staiion A Si oiion B ~e s+ ;---"\~ .~ ~ ~ Ea s ~ l ~ ~ \.. e "~\.. .J a b c d .J I 1 I I I I I I I I

Fig. 5-Station-to-station block with station-to-station track circuit designated thus in effect duplicating the function some instances is as long as 8 miles eration. Detailed explanations of the of "two-Iine control circuits ·in a con­ including as many as 5 track circuits means for controlling the timing to ventional single-track automatic block averaging 9,000 ft . long. Each time a prevent interference will be given in circuit scheme. pulse of energy ceases in a track cir­ another article in a forthcoming is­ Starting the explanation as of a cer­ cuit, some appreciable time is require d sue of Railway Signaling. The point tain instant, say that an impulse of to allow the relay to release and for here is that each impulse is of about d.c, energy about 0.4 seconds duration the so-called "charge " to dissipate 0.4 seconds duration, and depending is fed eastward from signal 8 on track from the track circuit so that the feed on lengths of track circuit and over­ circuit a, shown in Fig. 5, and is re­ . of the pulse in the opposite direction all station-to-station blocks and ballast layed through track Circuit b, c, d and will carry through. Thus the "off" conditions, the lengths of the "off" e. On receipt of this impulse the track period between eastward pulses must periods range from 2 seconds up to 3 268 RAILWAY SIGNAL ING April, 1946' seconds. The 0.4 seconds on and 2 ward impulses feeding from signal does not change the polarity or char­ seconds off totals about 25 impulses 5 to signal 8 continue so that signal acter of the impulses which are fedt per minute. 8 displays the green aspect. Thus as on east from signal 7 to signalS, non' applying to the control of station­ does the change affect the impulses; To Control Signal to Stop leaving signals such as signals 8 and which are being fed westward froml 5, the receipt of track circuit impulses signal 5 to signal 8. The track circuit scheme on this establishes controls for the green as­ Rock Island project holds a relay nor­ pect, but when no impulses are re­ Station Overlaps for Opposing Moves mally energized at signal 8 to cause ceived the contro ls are set for the red that signal to display the green aspect, aspect. As these station-leaving sig­ Thi s installation, except west of and a normally-energized relay at sig­ nals can display only red or green, Fa irbury in certain instances, includes nal 5 causes that signal to display this completes the discussion of the no intermediate signals as such to stop green. T hus these are practically control of such signals. opposing trains if they simultaneously equivalent to the normally-energized Normally the circuits are in opera­ pass opposing station-leaving signals, line relays in a convenlional single- tion to establish contr ols for the sig- such as signal S at station B and signal

Station II Siatso n B g ~ Wes f ~ Ea st- 1- +

T

eRfi

Fig. 4-Typical doubl e-end type track circuit arrangement

track automatic block system. Thus in nals to display the green aspect. If 8 at station A. Therefore , the control the Rock Island scheme the basic con­ station-entering signal 9, however, is of signal 5 for opposing moves ex­ tro ls are normally energized for both being held at the red aspect then the tends all the way through the station­ directions. W hile the controls of the controls are changed so that distant to-station block and the station block signals are affected to display certain signal 7 would display the yellow as­ at station A to signal 10 at the west aspects, the signals are not lighted un­ pect but nevertheless the impulses end, as shown in Fig. 6. Similarly, the til the approach of trains. must feed on eastward to control sig­ control of signal 8 extends through When an eastbound train enters the nal 5 for the green aspect. Briefly the station - to - station block and control limits of signal 8, the impulses this result is accomplished by chang­ through the station limits at station feeding eastward from signal 8 to ing the polarity of the impulses being B as far as the insulated joint on the signal 5 are stopped and that signal fed eastwar d in track circuit a from main track opposite the fouling point displays the red aspect but the west- signal 9 to signal 7; this, however, on the east end of the siding. W ith these overlaps, when a train passes signal 10 at station A it controls sig­ nal 5 at station B to red. When a westbound train passes the insulated joint on the main track opposite the fouling point at the east end of station B, it controls signal 8 at station A to red. With these overlaps there is no possibility of two opposing trains get­ ting proceed aspects to enter the same station-to-station block. In addition to the foregoing over­ laps for opposing train movements, shown in Fig. 6, the controls for the station-entering signal 3 and distant signal I extend to signal 10. Simi­ larity, the controls for the station-en­ tering signal 10 and the distant signal 12 extend to the insulated joint op­ posite the fouling point at the east end of station B. Thus, as an example, when an eastbound train passes signal 10 at station A and knocks signal 5 A typical double-distant signal location between stations at station B down to red, as described April, 1946 RAILWA Y SIGNALING 269 before, cont rols are also affect ed to in Fig. 6 and 7, is accomplished auto­ the switch circuit controll er on the west knock down signals 1 and 3 to the yel­ matically by train movements in con­ end switch of the passing track does low aspect. nection with a special arrangement of not, the latter contro lling a track re­ long and short tr ack circuits, switch peater, not always acting as such, by a Station Overlaps for circuit cont roller connections and re­ line control circu it. Thi s arrange­ Following Moves lays at the passing track locations. ment, providing a relay at each end of Functioning of this arrangement de­ the passing track, was found to be For following train movements in pends upon the direction in which the the most economical and effective ar­ station-to-station blocks in this in­ train is moving on the main line and rangemen t, and furtherm ore, addi­ stallation without any intermediate whether or not the tr ain is taking tional line wires are saved. signals, the overlaps differ from those siding. W hen the system was first designed, for opposing moves, being cut down a short track circuit was also used at to reduce tr ain delays which would be Short Track Circuits the west end of the passing tr ack, but incurred if the same overlaps were this required additional line wires for used that are employed for opposing Referring to Fi g. 6 and 7, it will the necessary overlap controls. F ur­ moves. Referring to F ig. 7, it will be be noted that at the east end of the thermore, there was a chance of the noted tha t for following moves, the passing tracks there is a short track inbound stick relay at the east end, controls for signals 1, 3 and 5 extend circuit through the switch, but that which controls the overlaps, not pick­ to signal 8, while the controls for sig­ there is no similar circuit at the west ing up, such as in the case of a light nals 12, 10 and 8 extend to signal S. end of the passing track circuit, the locomotive passing over the short Thus if a second train is following a long track circuit of the station block track circuit at the east end . Thi s was westbound train, signal 3 will clear to extending thro ugh the switch. A long because the contr ols had to pass from yellow after the first train has passed and short track circuit in this arrange­ the east end to the west end and back, signal S and a 3S-sec. time element has ment are employed for several rea- and in the long lapse of time in doing

Station II 5H Sfaft'on 8 fast - 30 JH ~ We5 t , ------(r - -- --'= - - - - 10 IH ,------

/2H /0 H

Fig. 6-Diagram of station overlaps for opp osing train movem ents elapsed to provide braking-distance sons, the most important being that a so the light engine passed off the short protection in the station block, and relay is required at the east end to pick track circuit befo re the control re­ signal 1 will clear to green. If the the inbound stick relay. The short cir­ turned. first train has already passed signal cuit, furthermore, is not part of the It should be understood that when 9, signals 1, 3 and 5 will all display actual overlap, thus allowing tr ains the switch at the west end is thrown green. to enter the siding without fouling it does not knock down the station­ the overlap, and thu s resulting in un­ departure signal at the next station to Control of Signal Overlaps necessary tr ain delays. the east, as the switch circuit con­ The switch circuit controller on the troller, as mentioned before, does not The control of signal overlaps for east end switch of the passing tr ack put a shunt on the track circuit of the opposing and following moves, shown shunts the short track circuit, while station block, but controls a track re-

Srcdion 8 5H Eas -i - ,.------1300 ------( JH St ation II ,.------/H ~ f7'~-'L + I I I

• __ -.!~ .J /2 H _I O~ .J 8 H )

Fig. 7-Diagram of stati on overlaps for following train movements 270 R AI L WA Y SIGNALI N G peater relay, not necessarily acting as tended to provide an add itional ~e t of tween stations with this arrangement such, which cont rols the signals in absolute signals and a set of distant as they are unnecessary. Referring t~ the vicinity of that pass ing track only. signals in the center of station-to-sta­ Fig. 3, with an eastbound train ap­ tion blocks in excess of 8 miles in proaching from the left signal I S will Overlap Signs length, as shown in F ig. 3, in orde r to be red, and signa l 14 will be clear pro­ allow trains to follow each othe r. F ur­ viding no trains are app roaching fro m Signal overlaps are indicated by thermore, the feat ure is accomplished the opposite direction . When the overlap signs mounted on the signals, by the use of coded track circuits eastbound train gets between signals as shown in Fig. 8. A train holding without line wires, and the layout is 14 and 12, signals 13 and 14 display

Fig . 8-Diagram of station-to-sta tion block, showing lise of overlap signs the main track at a meeting point is similar as that at a passing track loca­ red , signal IS clears, and signal 12 dis­ required to not pass beyond the over­ tion, but, without the passing track. plays gr een if there ar e no opposing lap sign or open a switch within the T he controls are norm ally dead and trains or trains in the same direction overlaps until the opposing train has the signal locations act as track repeat­ less than two signal blocks ahead. arrived and the siding switch has been ing locations except when a train is When the train passes signal 12 that set for entrance to the siding. The approaching and sets up the controls signal, as well as signals 11, 9, 7 trai n taking sidin g must open the for lighting the signals. After the and 5 display red, and signal 3 at switch before passing the overlap sign. train has passed, the system is again station B displays yellow. If there In certain instances overlap signs are dead and only acts as a track repeater is a following train, signal 12 will not moved for ward in or der to allow a location. T he signal arrangement con­ clear un til the first train is by signal train to advance further than usual, sists of two two-position norm al-clear 8, and likewise signal 8 will not clear such as in the case of the location of absolute signals, similar to those at for the second train until the first a water plug, or for some other op­ the head-block locations, to which train is by signal 4. When the first erating reasons . Ru le 292 applies, and two th ree-posi­ train is by signal 4, signal 3 is knocked tion normal-da nger distant signals down to red and signal 1 knocked Special Intermediate Signals similar to the distant signals for the down to yellow, signal 2 displaying passing stations, to which Rule 291 clear if the re are no opposing trains As mentioned before, west of Fair­ applies. or trains in the same direction less bur y the signal system has been ex- No overlap controls are used be- than two signal blocks ahead . In th e event an eastbound train passed signal 12 and a westbound train passed signalS simultaneously, they would both be protected by sig­ nals 7, 8, 9 and 10 from a head-on col­ lision. Such locations will be in service when the project is completed between P lymouth and Jansen, Norton and Dellvale, Dresden and Selde n, Selden and Rex ford, Leva nt and Brewster, Interior of in­ Brewster and Edson, and between strument case Beth une and Stratton. at a station­ leaving signal and station­ Previous Operation and Signal entering sig­ Protectio n n a l location Train movements in the territor y were formerly governed by timetable, manual block system and trai n order s. Block signa ls at isolated locations pro­ tecting switches, curves and stations were formerly located at Albright, Lincoln, Fairbury, Belleville, Court­ land, Alme na and Norton . The ma­ jority of this protection was A.P.E. controlled and was incorporated in the new installation and continued in serv­ ice as such as a matter of simplicit y. P reviously all main-li ne hand-throw switches were pr ovided with oil-burn ­ ing switch lamps . However, in the April, 1946 RAIL WAYSIGNALING 27 1 neW installation lamps on all such in service at th is crossing, the same gage side of the nearest rail so as to switches within 500 ft. of the signals being protected by a gate, operated by not interfere with Jordan ditchers do­ governing tr ain movements over the trainman, normally set agains t the ing maintenance of way work. switches have been removed from Santa Fe. The signals are painted red from service, being considered unnecessar y. the first ladd er brace down, including Elsewhere lamps have been continued Signals the ladder, and the upper portion of in service as before. the signals ar e painted alumin um, with T he signals on the new installation the exception of the .face of the InterJockings are the U nion T ype-H 2 plug- in searchlight background which is paint­ searchlight, designed for opera tion on ed black. On the permissive signals At the east end of Albright the 8 to 10 volts, d.c, All permissive sig­ the number , to the nearest tenth of Rock Island crosses a single-track line nals have 8-volt, 5-watt, single-fila­ a mile, is painted in black about mid­ of the U nion Pacific, this crossing be­ ment lamps, while absolute signals ways on the mast and on the portion ing protected by a gate , op e ~'ated by have 8-volt, 5-watt + 33/,-watt, dou­ which is painted aluminum. It has trainmen, normally set agamst the ble-filament lamps. All signals are been found on the Rock Island that V .P. The gate is equipped with cir­ equipped with hot- spot lenses, and by painting the numbers on the masts cuit controllers and a key box is used in some instances on curves, are there is only about 60 ft. difference in for setting signals against the Rock equipped with l C-deg . right or left­ visibility compared with the use of Island when the crossing is in use by hand deflecting prisms. enameled num ber plates. Absolute the U.P. Extending west from Al ­ bright, the Rock Island crosses a sin­ gle-track line of the Missouri Pacific at Lou isville, at which point a semi­ automatic interlocking is in service. Signals are contro lled from the depot at Louisville. At South Bend there is a crossing with a single-track line of the Chicago, Burlington &Quincy, this crossing being protected by an au­ tomatic interlocking. At Lincoln the re are two crossings, one with the Omaha, L incoln & Beatri ce and the other with the Mis­ souri Pacific. Train movements on both roads at the M.P . crossing are governed by Stop boards, but even­ Interior of in­ tually an automatic interlocking will stument case at a distant ­ be in service. The O.L.&B. crosses signal location the Rock Island by means of hand­ throw crossovers. At the same loca­ tion there is an interchange track lead­ ing from the Rock Island main line to the Chicago & North W estern . T he switch on the O .L.&B. end of the crossover and the Rock Island main­ line switch to the C.&N.W . tr ansfer are electrically locked. Be fore these switches may be operated, automatic signals must be placed at Stop . In ­ structions for operatin g these locks and switches are posted at each switch. The Rock I sland crosses a single­ track line of the Union Pacific at Fairbury, movement over which by Goth roads is governed by Stop board s. Between Thompson and Mohaska Signal masts are 12 ft. 8 in. over­ signals are not numbered thereby dis­ there is a crossing with a single-track all. The searc hlight units are mount­ tinguishing them fro m permissive sig­ line of the Burlington, which is pro­ ed on the left -hand side of the masts, nals. Overlap signs are painted black tected by an automatic interlocking. which is the track side, and 9 ft. above with white letters. Anothe r automa tic interlocking is in the center line of the rail. T wo­ service at Scandia, where there is a "arm" signals are on 17-ft. l Ovi n. In strume nt Cases crossing with a single-track line of masts, the units being mounted on l O­ M.P . At Scandia westward train ft. centers. The signals are mounted At each stati on-departure and sta­ movements fro m the Rock I sland sid­ on Massey and Permacrete single tion-leaving signal location a 4-ft. 11­ ing and house track are governed by section precast cyclindrical concrete in. welded sheet-metal instrument case color-light dwarf signals. Switches foundations, bolt centers on the is provided for sheltering the relays, must be prope rly lined for such move­ founda tions being 11:xi in. square. transfo rmers, rectifiers, track and n.;ents before a proceed indication of T he signals are ord inarily located 9 control batteries and other associated SIgnals can be given. Extending west feet from the gage side of the nearest equipment. For cut sections, a 2-ft. to Courtland, a single-track line of the rail. In certain instances, such as in 73/,-in. case is provided for the same Atchison, Topeka & Santa F e crosses cuts, and where there are ditches, the purpose. On the shelves in the cases the Rock Island. No interlocki ng is signals are located 18 ft . from the corrigated-rubber matti ng is used to 272 RAI LWAY SI GN ALING Ap ril. 1946

All instrument cases are prewired, read y for installation in the field, in the Rock Island signal shop s at Chicago. Upper left-The interior of the cases are painted before wiring is started. Upper right-Signal shop foreman (left) gives instructions concerning case wiring. N ote reels overh ead for case wire. Lower right-Signalmen complete wiring of case. Center left- Before the cases are shipped to the field each relay is strapped in place. Lower left-General view of instru­ ment cases being wired in the Rock Island signal shop s at Chicago before being shipped to the field for ins tallation April, 1946 RAI LWA Y SIG NA L I NG 273 prevent the apparatus fr om sliding due to any vibratio n that may be caused by passing trains. All cases are mounted on a Perrna­ crete single-slab precast concrete found ation at each end. Th ese slabs are 4 ft. and 5 ft. long, their use de­ pending L~ p on the grade and condition of the sOI L . All the instrument cases on this in­ stallation are prewired, ready for in­ stallation in the field. in the Rock Island signal shops at Chicago. Regu­ lar assembly-line procedure is used in this work, the first step being the Interior view painting of the insides of the cases of instrument case at track with aluminum paint. Rubber mat ­ ci rc u it c ur­ ting is inserted and the relays are put section 10ca­ in place and the cases completely rion, show ing, wired ready for service, except for the relays and pri­ connection of cables in the field. mary battery Before the cases are shipped to the field each relay is strapped in place with iron binding wire and pieces of cardboard to prevent any shifting or damage in shipment. U sing this pro ce­ dure , considerable time is saved on the installation and difficulties incur red during bad weather are eliminated. A unique device in wiring the cases was designed and built by the signal shop foreman to expedi te wiring. T he device consists of several collapsible reels mounted on a track over and in fro nt of wher e the wiring of cases is taking place. T he flexible case wire is wound on these reels, and they can be moved along in front of any case as circuits of the type used in this system, 100 to 110 volts, 60 cycles, a.c. required, thus keeping the wire and and the relay coil is by-passed when At each distant signal location 15 ordinary reels off the ground out of energy is being applied to the track. cells of Ed ison or Waterbury 1,000­ the way, and at the same time elimi­ Track feeds, therefore, in the rear of a.h. primary battery are provided for nating possible damage to the wire. each distant signal are provided with signal lighting and controls. This bat­ the by-pass feature. T he CD code tery is not located in the instrument following relays have a resistance of case, but in a separate Massey or Pe r­ Special Derrick 225 ohms with a charge of .06 amp. macrete precast concrete battery box and a release of .006 amp. The mini­ at the location. These boxes are 16­ On this pro ject a special hand­ mum d.p.u. is .013. cell capacity and are 34 in. by 34 in. operated derrick, fu rnished by F air­ The DM code transmitters are 75 by approximately 4 ft. Each coded mount Railway Motors, Inc., and coders for operation on 8 to 12 volts track circuit is fed by two cells of mounted on a trailer for towing by a d.c. The timing units operate on the Edi son or Waterbury 1,000-a.h. gang-type rail motor car, was used to same voltage. T rack front repeater primary battery in series and with a great advantage. The derr ick facili­ TFP relays are the Style DN-22A, 0.3-ohm variable track-limiting resis­ tated and eased labor considerably in rated at 2,000 ohms, while the T BP tance in series in the circuit. Primary the transportation and erection of sig­ track back repeater relays are the track cells, in practically all instances, nal masts, installation and placement Style D N- ll, rated at 1,000 ohms. are located in the instrument case at of instr ument cases, as well as in Other d.c. neutral relays are the the signal location. doing many other odd jobs. The D NL-4 type, rated at 78 ohms, and P ower at 110 volts, 60 cycles, a.c. tr ailer car is equipped with braces to are used for control of the lighting is received at all stations where sta­ be placed around the rail head at each of signals. tion-entering and station-departure corner of the car in front of the reels. signals are located. This power is cut The capacity of the derrick with the Power Supply through a watt -hour meter and is braces is 3,000 lb., while the capacity supplied by various public-utility con­ without them is 1,500 lb. At each station-entering and sta­ cerns. tion-dep arture signal location a set of Relays five cells of Gould NPRE , 80-a.h. Underground Cable lead-acid storage battery is prov ided T he track relays are the Type P -4, for signal lighting and controls. T his The undergr ound cable on this in­ two point, rated at 0.3 ohms, 0.1 volt, battery is located in the sheet-metal stallation is General, Okonite,Ana­ and drawing 320 mills. Single-point instrument case at the signal location. conda and Ke rite park way. T rack track relays are also used, being rated This battery is on a floating char ge circuit connections are single con­ at 0.3 ohms, 0.1 volt, and drawing 215 of 10 volts d.c. at 2.7 amps. f rom ductor No. 9. Between inst rument mills. Single-point track relays are either a Model DH -25 or 26 Fansteel cases and signals 4 and 6-conductor required in operating 11,000-ft. track LT.&T. selenium rectifier, rated at No. 14 is used. Between pole boxes 274 RAILWAY SIGNALING April. 1946

Genera l construction views in the field. Upper left-Special derrick in use, showing signal mast being hoisted in place. Upper right-Another view, showing special derrick in use. The mast has been placed and is being bolted down. Center lelt­ Signalman setting up instrum ent case for service. Center right-Signalman installing pole-line terminal box. Lower Jeft­ Signalmen installing bootleg risers and drilling rail for bonds. Lower rig ht-5earchlight signal being placed in service April, 1946 RAI LWAY SI GNALING 275 and instru ment cases lO-conductor circuits are protected by T ype TC-275 throughout. Rail joints are bonded No . 14 is in use. In the latter, the ar reste rs. with Ohio Brass Company rail-head .:able is run in a 5-ft. length of 2-in. type bonds. Fo r track circuit con­ iron pipe at the base of the pole as fire Track nections, bootleg risers with :rs-in. 64­ protection. P ar kway cable is used strand plug-type bonds with :rs-in. for connections between switch circuit Type RE and RA continuous in­ plugs are used. The underground controllers and the line and instrument sulated rail joints, manufactured by par kway cable is slack-looped in the cases. the Rai l J oint Company, are used riser terminated on the bond clamp at the top and packed in No-Ox-Id grease.

Switch Circuit Controllers

Each main -line switch is protected b)' a Un ion T ype U -5 switch circuit Left - Prima ry controller with four normal and four batter y at dis­ reverse contac ts. These controllers ar e tan t signal be­ the two-position type, with an ordi­ tween stations nary connecting rod to the foot of the nearest switch point. A bevelled hole is on the switch-point foot, and a ball and socket joint is on the circuit con­ t roller end of the connecting rod. A Western Ra ilroad Supply Company

Cases are wired with No. 16 flexible insulated wire for the lO-volt circuits, while N o. 10 flexible is used on the track circuits. All wiring in cases is marked by grey fiber tags, painted Righ t - Boot­ with black letters, and nailed on the leg conne ctions backboards. to track circuits. Below - A dis­ p atcher t el e ­ Line Wire phone i n use b y maintain e r W here line circuits are in service, as between the ends of passing tracks, N o.9 double braid w.p. Copperweld line wire is used. Such circuits are located on a botton lO-pin crossarm added to the existing W estern Union telegraph and telephone line. Signal line contr ol unit s are tied to iron terminal box atop a foot pedestal Hemingray No. 42 clear glass insula­ is used at all circuit controller loca­ tors, while power circuits are tied to tions. Connections between the box brown glazed porcelain insulators . and circuit controller are accomplished All insulators are on steel pins. in flexible Greenfield conduit.

Terminal Boxes Communications

At locations where there are line Dispatcher's telephones are located circuit dead-ends and line taps, a at both ends of sidings in territory Western Rai lroad Supp ly Company where automatic block signals 'Ire in cast-iron terminal box with two rows service. of six terminals each is mounted on T his installation was placed in the pole. Power and signal line taps service under the direction of C. R. into the box are made up of No . 14 Swenson, signal engineer, and under solid copper bridle wire with a 5/64­ the supervision of F red V. Laverty, in. wall. The bridle wires are pig­ engineer-inspector in the office of sig­ tailed and soldered to the line and nal engineer (now signal supervisor guided to the box by bridle rings on of the W estern division ). The maj or the unde rside of the crossarm. Brown items of signaling material were fur­ glazed porcelain cleves-type insulators nished by the U nion Switch & Signal are used for dead-ends. Company.

Lightning Protection (A detailed ar ticle explaining the Western Rai lroad Sup ply Company timi ng and operation of the coded No. 345 line arresters are used at all track circuits, as well as othe r control line-break locations, these arresters circuits in this system will appear in a being located in the instrument cases. forthcoming issue of Railway Signal­ Track circuits and signal mechanism ing.- Editor.)