87:
408:). The advent of all electric interlocking technology allowed for more automated route setting procedures as opposed to having an operator line each part of the route manually. The NX system allowed an operator looking at the diagram of a complicated junction to simply push a button on the known entrance track and another button on the desired exit track. The logic circuitry handled all the necessary actions of commanding the underlying relay interlocking to set signals and throw switches in the proper sequence, as required to provide valid route through the interlocking plant. The first NX installation was in 1937 at
390:
280:
31:
469:
627:"Electric locking that enforces cooperation between the Operators at two adjacent plants in such a manner that prevents opposing signals governing the same track from being set to proceed at the same time. In addition, after a signal has been cleared and accepted by a train, check locking prevents an opposing signal at the adjacent interlocking plant from being cleared until the train has passed through that plant."
343:
619:"Electric locking adapted to prevent any manipulation of levers that would bring about an unsafe condition in case a signal, switch, or other operated device fails to make a movement corresponding with that of the operating lever; or adapted directly to prevent the operation of one device in case another device, to be operated first, fails to make the required movement."
447:(US&S), and introduced in 1951. NX type systems and their costly pre-solid state control logic only tended to be installed in the busier or more complicated terminal areas where it could increase capacity and reduce staffing requirements. In a move that was popular in Europe, the signalling for an entire area was condensed into a single large
210:. By 1900, 54 electro-pneumatic interlocking plants, controlling a total of 1,864 interlocking levers, were in use on 13 North American railroads. This type of system would remain one of two viable competing systems into the future, although it did have the disadvantage of needing extra single-use equipment and requiring high maintenance.
480:, where the wired networks of relays are replaced by software logic running on special-purpose control hardware. The fact that the logic is implemented by software rather than hard-wired circuitry greatly facilitates the ability to make modifications when needed by reprogramming rather than rewiring. In many implementations, this
1160:
370:
Interlockings operated solely by electrical circuitry may be operated locally or remotely, with the large mechanical levers of previous systems being replaced by buttons, switches or toggles on a panel or video interface. Such an interlocking may also be designed to operate without a human operator.
181:
As technology advanced the railway signaling industry looked to incorporate these new technologies into interlockings to increase the speed of route setting, the number of appliances controlled from a single point and to expand the distance that those same appliances could be operated from the point
329:
Power interlockings may also use mechanical locking to ensure the proper sequencing of levers, but the levers are considerably smaller as they themselves do not directly control the field devices. If the lever is free to move based on the locking bed, contacts on the levers actuate the switches and
145:
received the first patent for interlocking switches and signals. In 1868, Saxby (of Saxby & Farmer) was awarded a patent for what is known today in North
America as “preliminary latch locking”. Preliminary latch locking became so successful that by 1873, 13,000 mechanical locking levers were
313:
In purely mechanical plants, the levers operate the field devices, such as signals, directly via a mechanical rodding or wire connection. The levers are about shoulder height since they must supply a mechanical advantage for the operator. Cross locking of levers was effected such that the extra
656:
allow continuous movements from any track on one side of the interlocking to any track on the opposite side without the use of a reverse move within the limits of the interlocking. This is true even if there are differing numbers of tracks on opposing sides, or if the interlocking has multiple
362:
that ascertain the state or position of each signal appliance. As appliances are operated, their change of position opens some circuits that lock out other appliances that would conflict with the new position. Similarly, other circuits are closed when the appliances they control become safe to
960:
A system whereby compressed water and air are used to transmit action from one end of a long tube to the other end. It can be effective, but it still qualifies as a mechanical system since the pressure is pre-loaded, and requires human action of the same sort that a pure mechanical system
73:
from being changed in an improper sequence. For example, interlocking would prevent a signal from being changed to indicate a diverging route, unless the corresponding points/switches had been changed first. In North
America, the official railroad definition of interlocking is:
571:"The combination of one or more electric locks or controlling circuits by means of which levers in an interlocking machine, or switches or other devices operated in connection with signalling and interlocking, are secured against operation under certain conditions."
334:. Before a control lever may be moved into a position which would release other levers, a signal must be received from the field element that it has actually moved into the position requested. The locking bed shown is for a GRS power interlocking machine.
306:, signals or other appliances are connected to the bars running in one direction. The bars are constructed so that if the function controlled by a given lever conflicts with that controlled by another lever, mechanical interference is set up in the
648:
depending on the movements available. Although timetables generally do not identify an interlocking as one or the other, and rule books do not define the terms, the terms below are generally agreed upon by system crews and rules officials.
839:
459:
and train tracking technologies. Away from complex terminals unit lever control systems remained popular until the 1980s when solid state interlocking and control systems began to replace the older relay plants of all types.
198:
in 1884. By 1891, there were 18 hydro-pneumatic plants, on six railroads, operating a total of 482 levers. The installations worked, but there were serious defects in the design, and little saving of labour was achieved.
165:(NYC&HRR). At the time, Toucey was General Superintendent and Buchanan was Superintendent of Machinery on the NYC&HRR. Toucey and Buchanan formed the Toucey and Buchanan Interlocking Switch and Signal Company in
1712:
173:
and the New York
Elevated Railroad Company in 1877–78. Compared to Saxby's design, Toucey and Buchanans' interlocking mechanism was more cumbersome and less sophisticated, and so was not implemented very widely.
611:"Electric locking taking effect upon the setting of a signal for a train to proceed, released by a passing train, and adapted to prevent manipulation of levers that would endanger an approaching train."
1215:
202:
The inventors of the hydro-pneumatic system moved forward to an electro-pneumatic system in 1891 and this system, best identified with the Union Switch & Signal
Company, was first installed on the
492:
that cannot be easily altered to both resist unsafe modification and meet regulatory safety testing requirements. As display technology improved, the hard wired physical devices could be updated with
603:"Electric locking effective while a train is approaching a signal that has been set for it to proceed and adapted to prevent manipulation of levers or devices that would endanger that train."
587:"Electric locking taking effect when a train passes a signal and adapted to prevent manipulation of levers that would endanger the train while it is within the limits of the route entered."
579:"Electric locking effective while a train occupies a given section of a route and adapted to prevent manipulation of levers that would endanger the train while it is within that section."
1910:
126:
the signal to proceed is withdrawn and sufficient time has passed to ensure that a train approaching that route has had opportunity to come to a stop before passing the signal.
516:
182:
of control. The challenge facing the signal industry was achieving the same level of safety and reliability that was inherent to purely mechanical systems. An experimental
665:
do not allow such movements as described above. Movements in an incomplete interlocking may be limited and may even require reverse movements to achieve the desired route.
249:, near Paris). By 1913, this type system had been installed on 83 railroads across 35 US states and Canadian provinces, in 440 interlocking plants using 21,370 levers.
1158:, Ronald A. McCann, "Entrance-exit route interlocking control apparatus", issued 11 September 1951, assigned to The Union Switch and Signal Company
455:
in the floors below that combined the vital relay based interlocking logic and non-vital control logic in one place. Such advanced schemes would also include
1207:
183:
120:
and a train is given a signal to proceed over that route, all switches and other movable appliances in the route are locked in position until either
234:
1015:
1084:
113:
Switches and other appliances in the route must be properly 'set' (in position) before a signal may allow train movements to enter that route.
1667:
1577:
1362:
1175:
1657:
1602:
66:. An interlocking system is designed so that it is impossible to display a signal to proceed unless the route to be used is proven safe.
1330:
Kleinstadt.zip "Full free version of an interlocking plant based on German Relay
Principles" (English, German, Dutch, French languages)
552:
540:
524:
162:
813:
676:
496:(computer monitors), which allowed changes in field equipment be represented to the signaller without any hardware modifications.
153:
The first experiment with mechanical interlocking in the United States took place in 1875 by J. M. Toucey and
William Buchanan at
1930:
1567:
727:
383:
76:
An arrangement of signals and signal appliances so interconnected that their movements must succeed each other in proper sequence
515:
in the UK. Second generation processor-based interlockings are known by the term "Computer Based
Interlocking" (CBI), of which
2084:
1925:
1884:
1298:
789:
595:"Route locking so arranged that a train, in clearing each section of the route, releases the locking affecting that section."
203:
1727:
1460:
1316:
939:
86:
2592:
1722:
1672:
1642:
1915:
1402:
1647:
106:, and may include crossings at grade and movable bridges. Some of the fundamental principles of interlocking include:
2021:
2016:
1905:
1252:
1617:
2557:
1874:
1355:
1125:"Buttons to Speed Travel in Subway: $ 2,000,000 System of Signals Soon to Be in Operation on Brooklyn IND Division"
375:, and the approach of a train sets its own route automatically, provided no conflicting movements are in progress.
318:
147:
50:
is an arrangement of signal apparatus that prevents conflicting movements through an arrangement of tracks such as
1692:
1940:
1920:
1513:
229:
in 1896. In North
America, the first installation of an interlocking plant using electric switch machines was at
170:
987:
1742:
1707:
1503:
1067:
837:, John Saxby & John Stinson Farmer, "Improved Switch and Signal", issued 11 August 1868
1335:
1321:
110:
Signals may not be operated to permit conflicting train movements to take place at the same time on set route.
2582:
1971:
1956:
1412:
363:
operate. Equipment used for railroad signalling tends to be expensive because of its specialized nature and
2587:
2165:
1632:
1422:
970:
2026:
1397:
1348:
401:
262:
2094:
1181:(Report). Railway Group Guidance Note GK/GN0802. London: Rail Safety and Standards Board. Archived from
1124:
2036:
2001:
1991:
1981:
1976:
1966:
1597:
1427:
696:
1155:
640:
and a series of switches. Railroad terminology defines the following types of interlockings as either
169:
in 1878. The first important installations of their mechanism were on the switches and signals of the
2280:
2077:
2031:
1986:
1889:
1747:
1592:
1544:
1392:
1387:
1024:
817:
556:
512:
477:
417:
409:
834:
2514:
2041:
2011:
2006:
1996:
1961:
1879:
1687:
1612:
1518:
1480:
528:
500:
444:
413:
175:
166:
903:
420:(NYCRR) at Girard Junction, Ohio in 1937. Another NYCRR installation was on the main line between
2552:
2265:
2106:
2046:
1844:
1829:
1587:
1559:
1379:
686:
187:
24:
1182:
213:
Interlockings using electric motors for moving switches and signals became viable in 1894, when
2424:
2248:
2180:
1824:
1814:
1763:
1682:
1677:
1407:
1290:
1284:
520:
433:
238:
222:
195:
55:
1251:
Defined by the
Railway Signal Association, which today is the Railway Signal Committee of the
1098:
2404:
2384:
2150:
2051:
1485:
1475:
1437:
1432:
821:
536:
284:
230:
154:
35:
2354:
2070:
1607:
1329:
429:
405:
439:
Other NX style systems were implemented by other railroad signal providers. For example,
8:
2429:
2201:
1834:
1717:
544:
493:
425:
310:
between the two bars, in turn preventing the conflicting lever movement from being made.
1276:
1266:
897:
2537:
2474:
2460:
2414:
2344:
1447:
1371:
1132:
1078:
701:
452:
43:
378:
GRS manufactured the first all-relay interlocking system in 1929. It was installed in
2542:
2287:
1869:
1773:
1549:
1294:
1059:
907:
795:
785:
759:
731:
379:
303:
103:
2499:
2469:
2464:
2135:
1935:
1864:
1839:
1819:
1637:
532:
489:
448:
389:
279:
246:
257:
Interlockings can be categorized as mechanical, electrical (electro-mechanical or
2547:
2419:
2374:
2314:
2216:
2140:
2130:
637:
481:
456:
421:
299:
191:
99:
70:
51:
30:
931:
221:(now in the Czech Republic). Another interlocking of this type was installed in
2409:
2394:
2319:
2292:
2221:
1662:
1508:
1495:
691:
504:
138:
95:
404:(CTC) interlocking system introduced in 1936 by GRS (represented in Europe by
2576:
2509:
2504:
2494:
2455:
2399:
2307:
2302:
2270:
2253:
2120:
2102:
1849:
1737:
1539:
1063:
735:
207:
158:
799:
763:
2439:
2369:
2329:
2231:
2211:
2196:
2175:
2170:
2160:
1783:
1627:
1534:
1417:
911:
631:
508:
468:
1809:
476:
Modern interlockings (those installed since the late 1980s) are generally
2364:
2324:
2236:
1470:
359:
274:
1050:
2521:
2487:
2482:
2434:
2359:
2334:
2275:
2241:
2125:
1859:
1732:
1697:
1455:
331:
142:
2062:
636:
Interlockings allow trains to cross from one track to another using a
2260:
2226:
2206:
2155:
2145:
1768:
1340:
983:
681:
364:
350:
Interlockings effected purely electrically (sometimes referred to as
451:
with a control panel in the operator's area and the equivalent of a
218:
2297:
2115:
1854:
1778:
503:" (SSI) is the brand name in trade of work of the first generation
485:
54:
or crossings. In North
America, a set of signalling appliances and
1105:. Simmons-Boardman Publishing Corporation.: 578–583 September 1949
758:(20). Simmons-Boardman Publishing Corporation: 1102. 26 May 1913.
58:
interlocked together are sometimes collectively referred to as an
1799:
1702:
428:, and this was quickly followed up by three installations on the
214:
69:
Interlocking is a safety measure designed to prevent signals and
902:. Rochester, New York: General Railway Signal Company. pp.
874:(4). Simmons-Boardman Publishing Corporation: 161. 28 July 1916.
400:
was the original brand name of the first generation relay-based
314:
leverage could not defeat the locking (preliminary latch lock).
2379:
1804:
1652:
1622:
896:
General Railway Signal Company (1913). Sperry, Henry M. (ed.).
812:
The first manufacturer of signal equipment, the predecessor of
548:
242:
226:
20:
1048:
895:
861:
859:
857:
855:
853:
851:
849:
1582:
1334:
Director of S&T Engineering, West Midlands Project Group
1013:
833:
443:
was the brand name of their Entrance-Exit system supplied by
355:
342:
295:
294:
is constructed, consisting of steel bars forming a grid. The
258:
123:
the train passes out of the portion of the route affected, or
1099:"Signaling and Interlocking On New Line of New York Subways"
472:
Computer-based controls for a modern electronic interlocking
1572:
846:
346:
Part of a relay interlocking using miniature plug-in relays
317:
The first mechanical interlocking was installed in 1843 at
141:
origin, where numerous patents were granted. In June 1856,
1091:
1117:
632:
Complete and incomplete interlockings (U.S. terminology)
1247:
1245:
1243:
1241:
1239:
1237:
1235:
1233:
98:, but usually includes additional appliances such as
217:
in Austria installed the first such interlocking at
1289:. Minneapolis, Minnesota: Voyageur Press. pp.
1271:. New York: Locomotive Engineering. pp. 143ff.
330:
signals which are operated electrically or electro-
1230:
1023:. West Henrietta, New York: Alstom. Archived from
976:
324:
1009:
1007:
1005:
964:
2574:
1154:
891:
889:
887:
885:
883:
881:
722:Josserand, Peter; Forman, Harry Willard (1957).
235:Chicago, St. Paul, Minneapolis and Omaha Railway
721:
393:Control panel for a US&S relay interlocking
1002:
784:. St Paul, Minnesota: MBI Publishing Company.
775:
773:
507:-based interlocking developed in the 1980s by
283:A view of the locking bed inside Deval Tower,
2078:
1356:
1325:(1927 New Zealand article by A. S. Henderson)
1017:A Centennial: History of Alstom Signaling Inc
878:
1668:Interoperable Communications Based Signaling
34:The tower and tracks at Deval interlocking,
23:. For use in electronics and computing, see
1603:Automatic Train Protection (United Kingdom)
770:
562:
416:, UK. The first US installation was on the
2085:
2071:
1363:
1349:
1083:: CS1 maint: location missing publisher (
936:Railways: History, Signalling, Engineering
463:
354:) consist of complex circuitry made up of
268:
163:New York Central and Hudson River Railroad
102:and Facing Point locks (US: switches) and
925:
923:
921:
814:Westinghouse Brake and Signal Company Ltd
1173:
677:Breath alcohol ignition interlock device
467:
388:
341:
278:
85:
81:
29:
2092:
1568:Advanced Civil Speed Enforcement System
1282:
1264:
1049:General Railway Signal Company (1936).
779:
728:Simmons-Boardman Publishing Corporation
384:Chicago, Burlington and Quincy Railroad
16:Arrangement of railway signal apparatus
2575:
1370:
1052:The NX System of Electric Interlocking
1014:Alstom Signaling Incorporated (2004).
918:
2066:
1728:Train Protection & Warning System
1344:
990:from the original on 28 November 2012
337:
290:In mechanical interlocking plants, a
252:
204:Chicago and Northern Pacific Railroad
1461:Integrated Electronic Control Centre
1103:Railway Signaling and Communications
1723:Train automatic stopping controller
1643:Continuous Automatic Warning System
1218:from the original on 8 October 2017
929:
547:, now Siemens), and (trademark of
171:Manhattan Elevated Railroad Company
94:A minimal interlocking consists of
13:
1403:Communications-based train control
942:from the original on 23 April 2012
932:"Toucey and Buchanan Interlocking"
866:"Landmarks in Signaling History".
186:interlocking was installed at the
19:For use of the term in music, see
14:
2604:
1309:
1253:Association of American Railroads
192:Philadelphia and Reading Railroad
1277:"History of Railway Signalling."
1073:from the original on 2010-11-28.
624:Check locking or traffic locking
148:London and North Western Railway
1885:Westinghouse Brake & Signal
1648:ContrĂ´le de vitesse par balises
1514:North American railroad signals
1200:
1167:
1148:
1042:
398:Entrance-Exit Interlocking (NX)
325:Electro-mechanical interlocking
90:A model board and lever machine
1743:Transmission balise-locomotive
1708:Sistema Controllo Marcia Treno
1618:Automatische treinbeĂŻnvloeding
1504:Application of railway signals
1268:Block and Interlocking Signals
954:
899:Electric Interlocking Handbook
827:
806:
743:
715:
371:These arrangements are termed
239:General Railway Signal Company
178:bought their company in 1882.
1:
1693:Punktförmige Zugbeeinflussung
1413:European Train Control System
1317:"Principles of Interlocking."
1174:Woolford, Paul (April 2004).
708:
445:Union Switch & Signal Co.
206:at its drawbridge across the
1633:Chinese Train Control System
1423:Radio Electronic Token Block
1176:Glossary of Signalling Terms
971:Lexikon der gesamten Technik
7:
1398:Centralized traffic control
669:
402:centralized traffic control
137:Railway interlocking is of
10:
2609:
2593:Railway signalling control
2293:Transfer table (traverser)
1598:Automatic train protection
1336:"Mechanical Interlocking."
726:(5th ed.). New York:
697:Safety instrumented system
272:
132:
18:
2530:
2448:
2343:
2281:ground-level power supply
2189:
2101:
1949:
1898:
1890:Westinghouse Rail Systems
1792:
1756:
1748:Transmission Voie-Machine
1593:Automatic train operation
1558:
1545:Track circuit interrupter
1527:
1494:
1446:
1393:Automatic block signaling
1388:Absolute block signalling
1378:
820:, Ltd. (headquartered in
818:Westinghouse Rail Systems
529:Union Switch & Signal
511:, GEC-General Signal and
418:New York Central Railroad
319:Bricklayers Arms Junction
176:Union Switch & Signal
1688:Pulse code cab signaling
1613:Automatic Warning System
1519:Railway semaphore signal
1481:Solid State Interlocking
1208:"Smartlock Interlocking"
662:Incomplete interlockings
563:Defined forms of locking
513:Westinghouse Signals Ltd
501:Solid State Interlocking
167:Harrisburg, Pennsylvania
2266:Railway electrification
1588:Automatic train control
1283:Solomon, Brian (2010).
1275:Ganguly, Sri Subhasis.
1058:. Rochester, New York.
780:Solomon, Brian (2003).
750:"Death of John Saxby".
687:Interlock (Engineering)
592:Sectional route locking
464:Electronic interlocking
373:automatic interlockings
269:Mechanical interlocking
261:-based), or electronic/
188:Bound Brook, New Jersey
25:Interlock (engineering)
1764:Level crossing signals
1683:Positive Train Control
1678:Linienzugbeeinflussung
1408:Direct traffic control
1265:Elliott, W.H. (1896).
653:Complete interlockings
521:General Railway Signal
473:
434:IND Fulton Street Line
394:
347:
287:
196:Lehigh Valley Railroad
91:
39:
2405:Platform screen doors
1486:Westlock Interlocking
1476:Rail operating centre
1438:Train order operation
1433:Track Warrant Control
1156:US patent 2567887
984:"Berliner Stellwerke"
822:Chippenham, Wiltshire
471:
392:
358:in an arrangement of
345:
285:Des Plaines, Illinois
282:
231:Eau Claire, Wisconsin
89:
82:Configuration and use
36:Des Plaines, Illinois
33:
2583:Interlocking systems
2355:Anti-trespass panels
1608:Automatic train stop
1279:Accessed 2011-05-06.
973:, entry "Stellwerke"
494:visual display units
430:New York City Subway
406:Metropolitan-Vickers
241:(GRS, now a unit of
2588:Rail infrastructure
2202:Classification yard
1136:. November 12, 1948
868:Railway Age Gazette
835:US patent 80878
752:Railway Age Gazette
484:logic is stored as
426:Rochester, New York
245:, headquartered in
2461:Motive power depot
2415:Signalling control
1448:Signalling control
1372:Railway signalling
1286:Railroad Signaling
1133:The New York Times
782:Railroad Signaling
702:Signalling control
616:Indication locking
474:
453:telephone exchange
395:
348:
338:Relay interlocking
288:
253:Interlocking types
92:
60:interlocking plant
44:railway signalling
40:
2570:
2569:
2288:Railway turntable
2109:
2060:
2059:
1870:Smith and Yardley
1300:978-0-7603-3881-0
1030:on 2 October 2011
791:978-0-7603-1360-2
380:Lincoln, Nebraska
2600:
2465:Railway workshop
2181:Transition curve
2151:Fastening system
2105:
2087:
2080:
2073:
2064:
2063:
1936:Transport Canada
1820:General Electric
1757:Crossing signals
1638:Cityflo 650 CBTC
1560:Train protection
1365:
1358:
1351:
1342:
1341:
1304:
1272:
1256:
1249:
1228:
1227:
1225:
1223:
1204:
1198:
1197:
1195:
1193:
1187:
1180:
1171:
1165:
1164:
1163:
1159:
1152:
1146:
1145:
1143:
1141:
1129:
1121:
1115:
1114:
1112:
1110:
1095:
1089:
1088:
1082:
1074:
1072:
1057:
1046:
1040:
1039:
1037:
1035:
1029:
1022:
1011:
1000:
999:
997:
995:
980:
974:
968:
962:
958:
952:
951:
949:
947:
927:
916:
915:
893:
876:
875:
863:
844:
843:
842:
838:
831:
825:
810:
804:
803:
777:
768:
767:
747:
741:
739:
724:Rights of Trains
719:
600:Approach locking
568:Electric locking
559:) are examples.
533:Hitachi Rail STS
449:power signal box
441:Union Route (UR)
247:Levallois-Perret
190:junction of the
146:employed on the
116:Once a route is
2608:
2607:
2603:
2602:
2601:
2599:
2598:
2597:
2573:
2572:
2571:
2566:
2526:
2444:
2420:Structure gauge
2375:Defect detector
2347:
2339:
2185:
2141:Clip and scotch
2131:Breather switch
2097:
2091:
2061:
2056:
1945:
1894:
1788:
1752:
1554:
1528:Train detection
1523:
1490:
1442:
1374:
1369:
1312:
1307:
1301:
1260:
1259:
1250:
1231:
1221:
1219:
1206:
1205:
1201:
1191:
1189:
1185:
1178:
1172:
1168:
1161:
1153:
1149:
1139:
1137:
1127:
1123:
1122:
1118:
1108:
1106:
1097:
1096:
1092:
1076:
1075:
1070:
1055:
1047:
1043:
1033:
1031:
1027:
1020:
1012:
1003:
993:
991:
982:
981:
977:
969:
965:
959:
955:
945:
943:
930:Calvert, J. B.
928:
919:
894:
879:
865:
864:
847:
840:
832:
828:
811:
807:
792:
778:
771:
749:
748:
744:
720:
716:
711:
706:
672:
634:
576:Section locking
565:
543:(trademarks of
523:, now Alstom),
466:
457:train describer
422:Utica, New York
340:
327:
277:
271:
255:
184:hydro-pneumatic
135:
84:
71:points/switches
28:
17:
12:
11:
5:
2606:
2596:
2595:
2590:
2585:
2568:
2567:
2565:
2564:
2563:
2562:
2561:
2560:
2545:
2540:
2534:
2532:
2528:
2527:
2525:
2524:
2519:
2518:
2517:
2512:
2507:
2502:
2492:
2491:
2490:
2485:
2477:
2472:
2467:
2458:
2452:
2450:
2446:
2445:
2443:
2442:
2437:
2432:
2427:
2422:
2417:
2412:
2410:Railway signal
2407:
2402:
2397:
2395:Level crossing
2392:
2387:
2382:
2377:
2372:
2367:
2362:
2357:
2351:
2349:
2341:
2340:
2338:
2337:
2332:
2327:
2322:
2320:Track geometry
2317:
2312:
2311:
2310:
2300:
2295:
2290:
2285:
2284:
2283:
2278:
2273:
2271:overhead lines
2263:
2258:
2257:
2256:
2246:
2245:
2244:
2234:
2229:
2224:
2222:Gauntlet track
2219:
2214:
2209:
2204:
2199:
2193:
2191:
2187:
2186:
2184:
2183:
2178:
2173:
2168:
2166:Minimum radius
2163:
2158:
2153:
2148:
2143:
2138:
2133:
2128:
2123:
2118:
2112:
2110:
2099:
2098:
2095:infrastructure
2090:
2089:
2082:
2075:
2067:
2058:
2057:
2055:
2054:
2052:United Kingdom
2049:
2044:
2039:
2034:
2029:
2024:
2019:
2014:
2009:
2004:
1999:
1994:
1989:
1984:
1979:
1974:
1969:
1964:
1959:
1953:
1951:
1947:
1946:
1944:
1943:
1938:
1933:
1928:
1923:
1918:
1913:
1908:
1902:
1900:
1896:
1895:
1893:
1892:
1887:
1882:
1877:
1872:
1867:
1862:
1857:
1852:
1847:
1842:
1837:
1832:
1827:
1822:
1817:
1812:
1807:
1802:
1796:
1794:
1790:
1789:
1787:
1786:
1781:
1776:
1771:
1766:
1760:
1758:
1754:
1753:
1751:
1750:
1745:
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1735:
1730:
1725:
1720:
1715:
1710:
1705:
1700:
1695:
1690:
1685:
1680:
1675:
1670:
1665:
1663:Integra-Signum
1660:
1655:
1650:
1645:
1640:
1635:
1630:
1625:
1620:
1615:
1610:
1605:
1600:
1595:
1590:
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1580:
1575:
1570:
1564:
1562:
1556:
1555:
1553:
1552:
1547:
1542:
1537:
1531:
1529:
1525:
1524:
1522:
1521:
1516:
1511:
1509:Cab signalling
1506:
1500:
1498:
1492:
1491:
1489:
1488:
1483:
1478:
1473:
1468:
1463:
1458:
1452:
1450:
1444:
1443:
1441:
1440:
1435:
1430:
1425:
1420:
1415:
1410:
1405:
1400:
1395:
1390:
1384:
1382:
1376:
1375:
1368:
1367:
1360:
1353:
1345:
1339:
1338:
1332:
1327:
1319:
1315:Calvert, J.B.
1311:
1310:External links
1308:
1306:
1305:
1299:
1280:
1273:
1261:
1258:
1257:
1229:
1212:www.alstom.com
1199:
1166:
1147:
1116:
1090:
1041:
1001:
975:
963:
953:
917:
877:
845:
826:
816:, and today’s
805:
790:
769:
742:
713:
712:
710:
707:
705:
704:
699:
694:
692:Lockout-tagout
689:
684:
679:
673:
671:
668:
667:
666:
663:
659:
658:
654:
633:
630:
629:
628:
625:
621:
620:
617:
613:
612:
609:
605:
604:
601:
597:
596:
593:
589:
588:
585:
581:
580:
577:
573:
572:
569:
564:
561:
555:(trademark of
527:(trademark of
519:(trademark of
505:microprocessor
465:
462:
414:Cheshire Lines
339:
336:
326:
323:
270:
267:
263:computer-based
254:
251:
155:Spuyten Duyvil
134:
131:
130:
129:
128:
127:
124:
114:
111:
83:
80:
62:or just as an
15:
9:
6:
4:
3:
2:
2605:
2594:
2591:
2589:
2586:
2584:
2581:
2580:
2578:
2559:
2556:
2555:
2554:
2551:
2550:
2549:
2546:
2544:
2541:
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2536:
2535:
2533:
2529:
2523:
2520:
2516:
2513:
2511:
2508:
2506:
2503:
2501:
2498:
2497:
2496:
2493:
2489:
2486:
2484:
2481:
2480:
2478:
2476:
2473:
2471:
2468:
2466:
2462:
2459:
2457:
2456:Coaling tower
2454:
2453:
2451:
2447:
2441:
2438:
2436:
2433:
2431:
2428:
2426:
2425:Signal bridge
2423:
2421:
2418:
2416:
2413:
2411:
2408:
2406:
2403:
2401:
2400:Loading gauge
2398:
2396:
2393:
2391:
2388:
2386:
2383:
2381:
2378:
2376:
2373:
2371:
2368:
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2361:
2358:
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2353:
2352:
2350:
2346:
2342:
2336:
2333:
2331:
2328:
2326:
2323:
2321:
2318:
2316:
2313:
2309:
2308:refuge siding
2306:
2305:
2304:
2301:
2299:
2296:
2294:
2291:
2289:
2286:
2282:
2279:
2277:
2274:
2272:
2269:
2268:
2267:
2264:
2262:
2259:
2255:
2254:tramway track
2252:
2251:
2250:
2247:
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2240:
2239:
2238:
2235:
2233:
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2228:
2225:
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2159:
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2149:
2147:
2144:
2142:
2139:
2137:
2134:
2132:
2129:
2127:
2124:
2122:
2119:
2117:
2114:
2113:
2111:
2108:
2104:
2100:
2096:
2088:
2083:
2081:
2076:
2074:
2069:
2068:
2065:
2053:
2050:
2048:
2045:
2043:
2040:
2038:
2035:
2033:
2030:
2028:
2025:
2023:
2022:North America
2020:
2018:
2015:
2013:
2010:
2008:
2005:
2003:
2000:
1998:
1995:
1993:
1990:
1988:
1985:
1983:
1980:
1978:
1975:
1973:
1970:
1968:
1965:
1963:
1960:
1958:
1955:
1954:
1952:
1948:
1942:
1939:
1937:
1934:
1932:
1929:
1927:
1924:
1922:
1919:
1917:
1914:
1912:
1909:
1907:
1904:
1903:
1901:
1899:Organisations
1897:
1891:
1888:
1886:
1883:
1881:
1878:
1876:
1873:
1871:
1868:
1866:
1863:
1861:
1858:
1856:
1853:
1851:
1850:Progress Rail
1848:
1846:
1843:
1841:
1838:
1836:
1833:
1831:
1828:
1826:
1823:
1821:
1818:
1816:
1813:
1811:
1808:
1806:
1803:
1801:
1798:
1797:
1795:
1793:Manufacturers
1791:
1785:
1782:
1780:
1777:
1775:
1772:
1770:
1767:
1765:
1762:
1761:
1759:
1755:
1749:
1746:
1744:
1741:
1739:
1738:Trainguard MT
1736:
1734:
1731:
1729:
1726:
1724:
1721:
1719:
1716:
1714:
1711:
1709:
1706:
1704:
1701:
1699:
1696:
1694:
1691:
1689:
1686:
1684:
1681:
1679:
1676:
1674:
1671:
1669:
1666:
1664:
1661:
1659:
1656:
1654:
1651:
1649:
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1644:
1641:
1639:
1636:
1634:
1631:
1629:
1626:
1624:
1621:
1619:
1616:
1614:
1611:
1609:
1606:
1604:
1601:
1599:
1596:
1594:
1591:
1589:
1586:
1584:
1581:
1579:
1576:
1574:
1571:
1569:
1566:
1565:
1563:
1561:
1557:
1551:
1548:
1546:
1543:
1541:
1540:Track circuit
1538:
1536:
1533:
1532:
1530:
1526:
1520:
1517:
1515:
1512:
1510:
1507:
1505:
1502:
1501:
1499:
1497:
1493:
1487:
1484:
1482:
1479:
1477:
1474:
1472:
1469:
1467:
1464:
1462:
1459:
1457:
1454:
1453:
1451:
1449:
1445:
1439:
1436:
1434:
1431:
1429:
1426:
1424:
1421:
1419:
1416:
1414:
1411:
1409:
1406:
1404:
1401:
1399:
1396:
1394:
1391:
1389:
1386:
1385:
1383:
1381:
1380:Block systems
1377:
1373:
1366:
1361:
1359:
1354:
1352:
1347:
1346:
1343:
1337:
1333:
1331:
1328:
1326:
1324:
1320:
1318:
1314:
1313:
1302:
1296:
1292:
1288:
1287:
1281:
1278:
1274:
1270:
1269:
1263:
1262:
1254:
1248:
1246:
1244:
1242:
1240:
1238:
1236:
1234:
1217:
1213:
1209:
1203:
1188:on 8 May 2016
1184:
1177:
1170:
1157:
1151:
1135:
1134:
1126:
1120:
1104:
1100:
1094:
1086:
1080:
1069:
1065:
1061:
1054:
1053:
1045:
1026:
1019:
1018:
1010:
1008:
1006:
989:
985:
979:
972:
967:
957:
941:
937:
933:
926:
924:
922:
913:
909:
905:
901:
900:
892:
890:
888:
886:
884:
882:
873:
869:
862:
860:
858:
856:
854:
852:
850:
836:
830:
823:
819:
815:
809:
801:
797:
793:
787:
783:
776:
774:
765:
761:
757:
753:
746:
737:
733:
730:. p. 5.
729:
725:
718:
714:
703:
700:
698:
695:
693:
690:
688:
685:
683:
680:
678:
675:
674:
664:
661:
660:
655:
652:
651:
650:
647:
643:
639:
626:
623:
622:
618:
615:
614:
610:
608:Stick locking
607:
606:
602:
599:
598:
594:
591:
590:
586:
584:Route locking
583:
582:
578:
575:
574:
570:
567:
566:
560:
558:
554:
550:
546:
545:Invensys Rail
542:
538:
534:
530:
526:
522:
518:
514:
510:
506:
502:
497:
495:
491:
487:
483:
479:
470:
461:
458:
454:
450:
446:
442:
437:
435:
431:
427:
423:
419:
415:
411:
407:
403:
399:
391:
387:
385:
381:
376:
374:
368:
366:
361:
357:
353:
344:
335:
333:
332:pneumatically
322:
320:
315:
311:
309:
308:cross locking
305:
301:
298:that operate
297:
293:
286:
281:
276:
266:
264:
260:
250:
248:
244:
240:
236:
232:
228:
224:
220:
216:
211:
209:
208:Chicago River
205:
200:
197:
193:
189:
185:
179:
177:
172:
168:
164:
160:
156:
151:
149:
144:
140:
125:
122:
121:
119:
115:
112:
109:
108:
107:
105:
101:
97:
88:
79:
77:
72:
67:
65:
61:
57:
53:
49:
45:
37:
32:
26:
22:
2440:Wayside horn
2390:Interlocking
2389:
2370:Catch points
2330:Water trough
2232:Passing loop
2212:Pocket track
2197:Balloon loop
2161:Ladder track
1880:Union Switch
1784:Wayside horn
1628:Catch points
1535:Axle counter
1466:Interlocking
1465:
1418:Moving block
1323:Interlocking
1322:
1285:
1267:
1220:. Retrieved
1211:
1202:
1190:. Retrieved
1183:the original
1169:
1150:
1138:. Retrieved
1131:
1119:
1107:. Retrieved
1102:
1093:
1051:
1044:
1032:. Retrieved
1025:the original
1016:
992:. Retrieved
978:
966:
956:
944:. Retrieved
935:
898:
871:
867:
829:
808:
781:
755:
751:
745:
740:Definitions.
723:
717:
645:
641:
635:
509:British Rail
498:
475:
440:
438:
397:
396:
377:
372:
369:
352:all-electric
351:
349:
328:
316:
312:
307:
291:
289:
256:
237:in 1901, by
212:
201:
180:
157:Junction in
152:
136:
117:
93:
75:
68:
64:interlocking
63:
59:
48:interlocking
47:
41:
2365:Buffer stop
2325:Water crane
2237:Track gauge
2176:Tie/Sleeper
2042:Switzerland
2017:New Zealand
2012:Netherlands
1718:Slide fence
1471:Lever frame
1140:27 December
1109:27 December
1034:27 December
994:24 November
946:28 December
478:solid state
360:relay logic
321:, England.
292:locking bed
275:Lever frame
2577:Categories
2538:Industrial
2522:Water stop
2483:for trains
2475:Roundhouse
2449:Structures
2435:Train stop
2385:Guard rail
2360:Block post
2348:and safety
2345:Signalling
2276:third rail
2249:Rail track
2242:dual gauge
2126:Baulk road
1950:By country
1733:Train stop
1698:RS4 Codici
1456:Block post
709:References
646:incomplete
557:Bombardier
273:See also:
143:John Saxby
2488:for goods
2430:Tell-tale
2261:Rail yard
2227:Guide bar
2207:Headshunt
2190:Trackwork
2156:Fishplate
2146:Date nail
2107:(history)
1957:Australia
1810:AŽD Praha
1769:Crossbuck
1673:Crocodile
1079:cite book
1064:184909207
961:requires.
736:221677266
682:Fail-safe
436:in 1948.
410:Brunswick
365:fail-safe
52:junctions
38:, in 1993
2543:Military
2500:building
2470:Platform
2380:Derailer
2298:Roll way
2217:Junction
2116:Axe ties
2047:Thailand
1855:Safetran
1845:Magnetic
1830:Griswold
1779:E-signal
1216:Archived
1192:20 April
1068:Archived
988:Archived
940:Archived
800:52464704
764:15110423
670:See also
642:complete
553:EBI Lock
541:Westrace
537:Westlock
525:MicroLok
486:firmware
367:design.
300:switches
194:and the
159:New York
2553:station
2548:Private
2495:Station
2171:Profile
2121:Ballast
1992:Germany
1982:Finland
1967:Belgium
1962:Bavaria
1865:Siemens
1840:Hitachi
1815:Federal
1800:Adtranz
1703:SelTrac
1550:Treadle
1496:Signals
912:3527846
638:turnout
551:), and
412:on the
382:on the
304:derails
233:on the
223:Westend
215:Siemens
161:on the
150:alone.
139:British
133:History
104:derails
96:signals
2315:Switch
2303:Siding
2103:Tracks
2037:Sweden
2032:Poland
2027:Norway
1997:Greece
1987:France
1972:Canada
1875:Thales
1805:Alstom
1774:Wigwag
1653:EBICAB
1623:Balise
1297:
1162:
1062:
910:
841:
798:
788:
762:
734:
657:sides.
549:Alstom
531:, now
488:or in
356:relays
296:levers
243:Alstom
227:Berlin
219:Přerov
100:points
56:tracks
21:Hocket
2531:Types
2510:ghost
2505:clock
2479:Shed
2093:Rail
2007:Japan
2002:Italy
1977:China
1911:AREMA
1860:Saxby
1713:SACEM
1658:IIATS
1583:ATACS
1428:Token
1222:4 May
1186:(PDF)
1179:(PDF)
1128:(PDF)
1071:(PDF)
1056:(PDF)
1028:(PDF)
1021:(PDF)
906:–12.
482:vital
259:relay
225:near
46:, an
2558:list
2515:list
2136:Cant
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