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track. The movement of trains running in that direction would be governed by the automatic block signals which would supersede the normal superiority of trains, where such systems applied. Movement of trains operating against the established flow of traffic would still require train orders or other special manual protections to prevent a collision. Therefore, under ABS operation trains moving in the wrong direction incurs additional operational overhead and may not be well supported by the track infrastructure.
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Most ABS systems use three- or four-block arrangements, where an obstruction in the first block will prompt a warning upon entering the second block, and allow full speed for trains entering the third. Where blocks are short or higher capacity is needed, four or more blocks are used; trains are then
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about 1863, a couple of decades before other
American railroads began using it. This system required a railroad employee stationed at each signal to set the signals according to instructions received by telegraph from dispatchers. English railroads also used a "controlled manual" block system, which
169:
However, as time went on, many railroads came to see automatic block signaling as cost effective, since it reduced the need for employees to manually operate each signal, reduced the repair costs and damage claims resulting from collisions, made possible a more efficient flow of trains, reduced the
370:
The most common forms of ABS were implemented on double-track rail lines in high-density areas that exceeded the capacity provided by either timetable and train order or other manual forms of signaling. ABS would be set up in such a way to cover train movements only in a single direction for each
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systems required human operators. The automatic operation comes from the system's ability to detect whether blocks are occupied or otherwise obstructed, and to convey that information to approaching trains. The system operates without any outside intervention, unlike more modern traffic control
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given multiple warnings of an impending obstruction. For basic block status, the red/yellow/green system of signaling is nearly universal, with red indicating an obstructed block, yellow indicating that an obstructed block is ahead, and green indicating that no obstruction is to be expected.
112:. One train waited upon another, according to the instructions in the timetable, but if a train was delayed for any reason, all other trains might be delayed, waiting for it to appear at the proper place where they could pass safely. Operation of trains by timetable alone was supplemented by
161:
reported that of the 48,743 miles (78,444 km) of railroad in the United States that used a block system, there were 41,916 miles (67,457 km) protected by the manual block system, and only 6,827 miles (10,987 km) of automatic block, on either single or
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88:. The system controls the movement of trains between the blocks using automatic signals. ABS operation is designed to allow trains operating in the same direction to follow each other in a safe manner without risk of rear-end collision.
1347:
147:) that made contact with passing trains in order to trigger motor-operated mechanical signals. The first use of track circuit operated automatic block signalling in Britain was installed in 1902 by the
338:
functions. It is standard practice to have an overlap after the signal. These overlaps can vary from 50 to 440 yards (46 to 402 m), with the standard overlap being 200 yards (180 m).
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on its opening in 1893. Instead of track circuits, the system used a setup of trackside mechanical, and later, electrical instruments (both functionally similar to
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would send train orders to stations manned by telegraphers, who wrote them down on standardized forms and handed them to train crews as they passed the station.
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Report of the
Interstate Commerce Commission on Block-Signal Systems and Appliances for the Automatic Control of Railroad Trains
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number of hours trains and crews sat idle, and decreased overall transit times from point to point.
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in
England, where the horizontal black bar at the top of the ID plate indicates an automatic signal
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between
Andover junction and Grateley which operated pneumatically powered mechanical signals.
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432:"SSP011 07-91 Controlled, Semi-Automatic and Automatic Colour Light Signals in TCB areas"
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The first use of automatic block signalling in the United
Kingdom was installed on the
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The introduction of ABS reduced railways' costs and increased their capacity. Older
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405: – Electrical device used to detect the presence of trains on rail tracks
80:) in the UK, is a railroad communications system that consists of a series of
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The earliest way of managing multiple trains on one track was by use of a
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1215:
399: – A person who controls the passage of a train by a level crossing
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1139:
208: in this section. Unsourced material may be challenged and removed.
594:"GKRT0064 Iss 1: Provision of Overlaps, Flank Protection and Trapping"
96:
systems that require external control to establish a flow of traffic.
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A manual block system in the United States was implemented by the
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557:"Sign AC03 Iss 1: Automatic Signal Sign and Identification Plate"
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that divide a railway line into a series of sections, called
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In the UK, automatic signals are used where there are no
699:. Pennsylvania Railroad. April 25, 1965. p. 51.
600:. Rail Safety and Standards Board. February 12, 2000
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633:. Rail Safety and Standards Board. October 31, 2016
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46:automatic block signal at Milepost 122.2 on the
438:. Rail Safety and Standards Board. July 1, 1991
545:(2nd ed.). Addlestone, Surrey: Ian Allan.
541:Kitchenside, Geoffrey; Williams, Alan (2016).
519:. Washington: Government Printing Office. 1907
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8:
1105:Interoperable Communications Based Signaling
1040:Automatic Train Protection (United Kingdom)
48:Reading Blue Mountain and Northern Railroad
800:
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693:CT-400 Rules for Conducting Transportation
509:
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393: – Section of railway without signals
354:each governing one direction of travel on
134:New York Central and Hudson River Railroad
291:Learn how and when to remove this message
224:Learn how and when to remove this message
1510:1871 establishments in the United States
1005:Advanced Civil Speed Enforcement System
420:
132:was adapted for use in the U.S. by the
271:Please improve this section by adding
1165:Train Protection & Warning System
7:
898:Integrated Electronic Control Centre
661:"Railroad's Traffic Control Systems"
206:adding citations to reliable sources
1160:Train automatic stopping controller
1080:Continuous Automatic Warning System
543:Two Centuries of Railway Signalling
840:Communications-based train control
25:
464:Gwyer, William L. (May 1, 2006).
1525:Railway signalling block systems
249:
182:
1322:Westinghouse Brake & Signal
1085:ContrĂ´le de vitesse par balises
951:North American railroad signals
728:"Centralized Traffic Control".
659:Bryan, Frank W. (May 1, 2006).
565:Rail Safety and Standards Board
193:needs additional citations for
1180:Transmission balise-locomotive
1145:Sistema Controllo Marcia Treno
1055:Automatische treinbeĂŻnvloeding
941:Application of railway signals
307:A caution signal at ME 130 at
159:Interstate Commerce Commission
27:Railroad communications system
1:
1130:Punktförmige Zugbeeinflussung
850:European Train Control System
334:, neutral sections, or other
273:secondary or tertiary sources
1070:Chinese Train Control System
860:Radio Electronic Token Block
835:Centralized traffic control
386:Centralized traffic control
1541:
1035:Automatic train protection
141:Liverpool Overhead Railway
70:automatic block signalling
29:
18:Automatic block signalling
1327:Westinghouse Rail Systems
1185:Transmission Voie-Machine
1030:Automatic train operation
982:Track circuit interrupter
830:Automatic block signaling
825:Absolute block signalling
734:Union Switch & Signal
381:Absolute block signalling
116:beginning in 1854 on the
62:Automatic block signaling
32:Absolute block signalling
1125:Pulse code cab signaling
1050:Automatic Warning System
956:Railway semaphore signal
918:Solid State Interlocking
669:. ABC's of Railroading.
627:"SSP020 05-78: Overlaps"
356:Norfolk Southern Railway
114:telegraphed train orders
56:Jim Thorpe, Pennsylvania
30:Not to be confused with
1025:Automatic train control
751:Solomon, Brian (2010).
1515:1871 in rail transport
1201:Level crossing signals
1120:Positive Train Control
1115:Linienzugbeeinflussung
845:Direct traffic control
367:
352:position light signals
330:, manually controlled
312:
260:relies excessively on
58:
52:Lehigh Valley Railroad
923:Westlock Interlocking
913:Rail operating centre
875:Train order operation
870:Track Warrant Control
717:. Rule 251 Section 2.
646:registration required
613:registration required
580:registration required
451:registration required
364:Pennsylvania Railroad
349:
306:
241:In the United Kingdom
129:Pennsylvania Railroad
120:. A railroad company
42:
1045:Automatic train stop
342:Single-direction ABS
309:Beaconsfield station
202:improve this article
152:West of England line
50:Lehigh Line (former
328:facing and trailing
74:track circuit block
1520:1871 introductions
885:Signalling control
809:Railway signalling
755:Railroad Signaling
715:CSX Transportation
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1307:Smith and Yardley
770:978-0-7603-3881-0
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16:(Redirected from
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1373:Transport Canada
1257:General Electric
1194:Crossing signals
1075:Cityflo 650 CBTC
997:Train protection
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567:. June 6, 2015
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466:"Train Orders"
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350:A pair of ABS
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332:level crossing
321:flat junctions
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281:February 2022
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258:This section
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191:This section
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157:By 1906, the
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1317:Union Switch
1221:Wayside horn
1065:Catch points
972:Axle counter
903:Interlocking
855:Moving block
829:
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729:
723:
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692:
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676:February 24,
674:. Retrieved
664:
654:
637:February 18,
635:. Retrieved
630:
621:
604:February 18,
602:. Retrieved
597:
588:
571:February 21,
569:. Retrieved
560:
551:
542:
523:February 18,
521:. Retrieved
515:
485:
475:February 18,
473:. Retrieved
469:
459:
442:February 21,
440:. Retrieved
435:
369:
360:Enola Branch
336:interlocking
317:ground frame
314:
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278:
259:
235:
220:
214:October 2023
211:
200:Please help
195:verification
192:
168:
164:double track
156:
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103:
93:manual block
90:
85:
77:
73:
69:
65:
61:
60:
36:
1479:Switzerland
1454:New Zealand
1449:Netherlands
1155:Slide fence
908:Lever frame
68:), spelled
1504:Categories
1387:By country
1170:Train stop
1135:RS4 Codici
893:Block post
631:RSSB.co.uk
598:RSSB.co.uk
561:RSSB.co.uk
491:US 918539A
436:RSSB.co.uk
415:References
262:references
122:dispatcher
72:or called
1394:Australia
1247:AŽD Praha
1206:Crossbuck
1110:Crocodile
136:in 1882.
106:timetable
1484:Thailand
1292:Safetran
1282:Magnetic
1267:Griswold
1216:E-signal
730:Bulletin
375:See also
362:(former
145:treadles
1429:Germany
1419:Finland
1404:Belgium
1399:Bavaria
1302:Siemens
1277:Hitachi
1252:Federal
1237:Adtranz
1140:SelTrac
987:Treadle
933:Signals
732:(176).
397:Flagman
100:History
82:signals
1474:Sweden
1469:Poland
1464:Norway
1434:Greece
1424:France
1409:Canada
1312:Thales
1242:Alstom
1211:Wigwag
1090:EBICAB
1060:Balise
767:
666:Trains
497:
470:Trains
149:LSWR's
86:blocks
1444:Japan
1439:Italy
1414:China
1348:AREMA
1297:Saxby
1150:SACEM
1095:IIATS
1020:ATACS
865:Token
697:(PDF)
54:) in
1368:IRSE
1363:HMRI
1272:Hall
1015:ASFA
1010:ALSN
765:ISBN
678:2022
639:2022
606:2022
573:2022
525:2022
477:2022
444:2022
108:and
1378:UIC
1358:FRA
1353:ERA
1343:AAR
1262:GRS
358:'s
264:to
204:by
78:TCB
66:ABS
1506::
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