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staffing. In the
Portuguese system, although the authority of train movement on the main lines is the sole responsibility of the stations along those lines, a regulating post oversees them and, in case of disagreement, instructs stations as to how the traffic should be organised. On the other hand, each train timetable indicates all interactions with other trains (e.g. crossings with other trains; trains that they overtake; trains that overtake them) clearly marked at the stations at which those interactions should occur. Any deviation from that—arising, for example, from delays or extra trains—must be provided to the train crews in writing. Despite the general practice that, when two trains cross, they both stop at the nearest station, this system allows for good average speeds for fast trains similar to those on an automatic-signalling line. However, if minor delays occur and then proliferate, longer delays can arise as the system's additional safety mode is invoked (i.e. the paperwork-intensive process of updating train-movement instructions to reflect the altered crossing patterns). Such delays would not happen, at least not for the same reason, on an automatic-signalling line.
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be accepted, the signaller will set any relevant points (turnouts) and signals and signal acceptance, and then request acceptance by the next signal box along the line. When the train has passed, the signals behind it will be set back to danger and the signaller will inform the next signal box when the train has left the section. These messages are conveyed by telegraph instruments with a key that is pressed to sound a bell at the remote signal box. Such systems, such as
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block, so both blocks are marked as occupied. That ensures there is slightly less than one block length on either end of the train that is marked as occupied, so any other train approaching that section will have enough room to stop in time, even if the first train has stopped dead on the tracks. The previously-occupied block will only be marked unoccupied when the end of the train has entirely left it, leaving the entire block clear.
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This is a system for use on single track railways, which requires neither the use of tokens nor provision of continuous train detection through the section. The signalling is designed in such a way that the controlling signals will only allow one train to enter the line at any one time. The signaller
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Used on multiple track sections whereby the passage of trains from one point to the next is controlled by instruments connected by telegraph wires. In the simplest case with three signal boxes on a stretch of line without junctions, the central of the three boxes will receive a request for a train to
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Popular on single track lines in North
America up until the 1980s, Train Order operation was less a block system and more of a system of determining which trains would have the right of way when train movements would come into conflict. Trains would make use of a predetermined operating plan known as
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by preventing collisions between trains. The basic principle is that a track is broken up into a series of sections or "blocks". Only one train may occupy a block at a time, and the blocks are sized to allow a train to stop within them. That ensures that a train always has time to stop before getting
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Like the manual block systems outlined above, automatic systems divide the route into fixed blocks. At the end of each block, a set of signals is installed, along with a track-side sensor. When a train passes the sensor, the signals are triggered to display the "block occupied" aspect on the signals
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A driver approaching a single track section would get the token, and uses it as the authority to enter the block section. He would surrender the token at the other end of the section. This caused problems if one train was to be followed by another in the same direction, as the staff would not be at
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This leads to the possibility that a train may break down on the tracks, and the following train suddenly comes upon it when rounding a bend, or suddenly sees its rear signal lamp. In these situations there will not be enough room for the train to stop before it collides. This is known as the "brick
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The basic problem for train control is inability to change course and the relatively long stopping distances of a loaded train. This is often far longer than the operator's eyesight, especially at night or in bad weather. The distances are great enough that local terrain may block sighting of trains
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Block systems have the disadvantage that they limit the number of trains on a particular route to something fewer than the number of blocks. Since the route has a fixed length, increasing the number of trains requires the creation of more blocks, which means the blocks are shorter and trains have to
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Trains operate according to a strict timetable, and as such, cannot leave a station until an appointed time, and until any other trains they were to meet at that station have arrived. If one train is delayed, all trains it is scheduled to meet are delayed. This can quickly lead to all trains on the
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If a single track branch line is a dead end with a simple shuttle train service, then a single token is sufficient. The driver of any train entering the branch line (or occupying any part of it) must be in possession of the token, and no collision with another train is possible. For convenience in
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The key issue is that a given train cannot safely see another train in time to stop. However, this is not true for trains that are equipped with some sort of inter-train communications system. In this case, any given train can keep itself at a safe distance from other trains, without the need for
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In terms of ensuring safety, the real consideration is the stopping distance of a given train and the distance at which it can spot another train. Blocks do not actually implement this concept, they implement a signalling system that ensures the worst performing train on a line has enough time to
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In general, the system dictates that a block is assumed to be closed; that is, permission must be obtained before a train is allowed to enter a block at one station en route to the other. However, in France, on multiple tracks, the block is usually open in unidirectional track sections. That is,
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A modern variation of the One Train
Working system operates without any train staff. On these lines the clearance of the controlled branch entry signal is the driver's sole authority to enter the branch, and once the train has passed that signal, the interlocking will hold it at 'danger' (and the
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Ordinary train staff (OTS) was therefore extended: if one train was to be followed by another in the same direction, the driver of the first train was required to be shown the token, but not take possession of it (in theory he was supposed to physically touch the token, but this was not strictly
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In North
American train order system was often implemented on top of other block systems when those block systems needed to be superseded. For example, where manual or automatic block was implemented, train orders would be used to authorize movements into occupied blocks, against the current of
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In this system, the occupation of a given section of track between two stations is agreed between its station masters, via telephone. For greater safety there can be additional layers of protection; for example, a regulating post, with supervisory powers connected to all the stations in a line;
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is used to control the passage of trains between the blocks. When a train enters a block, signals at both ends change to indicate that the block is occupied, typically using red lamps or indicator flags. When a train first enters a block, the rear of the same train has not yet left the previous
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Blocks avoid these problems by ensuring there is a certain minimum distance between trains, a distance that is set to ensure that any train operating within the speed and load limits, will have time to stop before reaching a train ahead of it. There are many ways of implementing such a system.
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In
Portugal, the telephonic block was the main safety system across the national railway network until the mid-1990s due to lack of resources. Thus, it evolved to try to provide multiple layers of safety on busy single-track lines with diverse train types, albeit at the cost of high levels of
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Portugal, Spain and France still use this system on at least some main lines, although the total length of track governed by this system is decreasing rapidly due to its labour intensity and its inherent perceived lack of safety, relying as it does primarily on human communication (sometimes
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at either end of that block. In most systems the signals do not immediately return to the "block empty" aspect when the train leaves, instead there is some sort of mechanical delay that retains the block occupied aspect, or more commonly, presents a "proceed with caution" aspect.
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after a station confirms that a previous train has vacated the block, the next train travelling in the same direction can immediately enter the block, with the station master at the entry station informing the exit station of the time that the train entered the block.
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design. The bell is in the bottom part with the key for sounding the bell in the next signal box. Above that is the switch for indicating whether the section of line is clear (green), there is a train in that section (red) or the normal "line blocked" state
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In such systems, any train on the route can listen for signals from all the other trains, and then move in a way to ensure they have enough distance to stop. Early moving block systems used a cable strung along the rail line. Trains would use
235:. This provides the ability to implement a set of blocks using manual signalling based at these locations. In this case, the station operator places a flag indicating a train has just left the station, and removes it only after a fixed time.
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at the start of the branch. Continuous train detection on the branch is not required. Safety is ensured by the interlocking circuitry, and if a track-circuit failure occurs then special emergency working by pilotman must be introduced.
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to inject signals into the line indicating their location. The cable could also provide that location in a variety of ways that could be picked up by a sensor on the train. More modern systems may use off-board location systems like
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and yards, but not normally within the yards, where some other method is used. Any block system is defined by its associated physical equipment and by the application of a relevant set of rules. Some systems involve the use of
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Authority to occupy a block is conveyed to trains by the use of wayside signals manually controlled by human operators following various procedures to communicate with other block stations to ensure separation of trains.
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wall criterion". Even in the case of two fully operational trains, differences in speed may be great enough that a faster train may not have time to slow down to match the speed of the one in front before it hits it.
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572:. Previously, separation of trains had relied on strict timetabling only, which was unable to allow for unforeseen events. In 1898, Martin Boda described a switching theory for block systems.
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Authority to occupy a block is provided by physical possession of a token by train staff that is obtained in such a way that ensures that only one train is in a section of track at a time.
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The advantage to moving block systems is that there is no fixed number of trains on the line, because there are no fixed blocks. This can greatly improve route capacity, as seen in the
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stop. This means any train with better stopping performance is forced to operate at speeds that are lower than its maximum, unless all of the trains on a particular line are identical.
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at the far end of the section must visually check that the whole train has left the section and has not become divided by confirming the train is 'complete with tail lamp'.
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systems to railway mainlines. There is a wide variety of systems, and an even wider variety of signals, but they all work in roughly the same fashion.
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passing it from hand to hand, the token was often in the form of a staff, typically 800 mm long and 40 mm diameter, and is referred to as a
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the timetable which made use of fixed passing locations often referred to as stations. Amendments to the operating plan would come from a
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ahead, and even the routing of the rails, around bends and such, may make it difficult to even know where to look for another train.
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This method is not authorised for use in many high-traffic railway systems because it is potentially unsafe and highly inefficient.
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764:(in German). Neue Folge XXXV (1–7). Wiesbaden, Germany: C. W. Kreidel's Verlag: 1–7, 29–34, 49–53, 71–75, 91–95, 111–115, 133–138.
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Organ fĂĽr die
Fortschritte des Eisenbahnwesens in technischer Beziehung – Fachblatt des Vereins deutscher Eisenbahn-Verwaltungen
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signal cannot be cleared a subsequent time) until the branch service train, on its return journey has sequentially operated two
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in the form of train orders, transmitted to the trains via intermediaries known as agents or operators at train order stations.
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operate at lower speeds in order to stop safely. As a result, the number and size of blocks are closely related to the overall
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involving more than just the two station masters at each end of the block) and simple railway interlockings at the stations.
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Automatic block signaling uses a series of automated signals, normally lights or flags, that change their display, or
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Boda, Martin (1898). "Die
Schaltungstheorie der Blockwerke" [The switching theory of block systems].
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dangerously close to another train on the same line. The block system is referred to in the UK as the
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417:, were developed in the nineteenth century and are still used extensively in Britain and Australia.
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or track-side indicators, and send the data between the trains using various radio-based methods.
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780:(NB. This series of seven articles was republished in a 91-pages book in 1899 with a foreword by
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followed). He was given a written authority to enter the single line section, referred to as the
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at the other end of the section, and a second train could follow in possession of the staff.
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railways, on which there is a danger of both head-on and rear-end collision, as opposed to
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have become popular since the required technology first started appearing in the 1970s.
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This method is not currently authorised for use in the UK. A similar system, known as
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Most rail routes have a sort of natural block layout inherent in the layout of the
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This is assuming the trains themselves are not changing. A counterexample is the
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in which he proposed block working for general use as a safer way of working on
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808:(1 ed.). Binghamton, New York, USA: Litton Educational Publishing, Inc. /
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679:"Bulletin". Australian Railway Historical Society. March 1961. pp. 43–51.
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In UK terminology, this method of working was originally referred to as
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while others do not. Some systems are specifically designed for
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280:, Somerset & Dorset Railway, 1876) its use was condemned.
29:
874:
Vanns, Michael A. (2012). "The 1870s
Signalling Revolution".
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The first use of block working was probably in 1839 when a
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timetable (Portugal); and/or computer assistance (France).
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traffic or where no current of traffic was established.
720:"Moving block signals finally go ahead on Jubilee Line"
878:. abc (2nd ed.). Hersham, Surrey, UK: Ian Allan.
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The
Electric Telegraph: A Social and Economic History
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Ordinary train staff and ticket (OTST) or (OTS&T)
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859:(2nd revised ed.). Oxford Publishing Company.
201:, on which the main danger is rear-end collisions.
60:. Unsourced material may be challenged and removed.
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564:, who had built the Clay Cross system, published
184:Block systems are used to control trains between
804:(May 1972). "Reference Notations to Chapter 1".
382:These came in two sizes, large and miniature.
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855:Kichenside, Geoffrey; Williams, Alan (2008).
8:
1220:Interoperable Communications Based Signaling
1155:Automatic Train Protection (United Kingdom)
370:. He could then proceed, surrendering the
148:enable the safe and efficient operation of
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901:
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120:Learn how and when to remove this message
657:, The Block System: 1: Basic Principles.
403:Telegraph block instruments of standard
357:the correct end after the first train.
1120:Advanced Civil Speed Enforcement System
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623:
566:Telegraphic Railways or the Single Line
313:One train working (without train staff)
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1280:Train Protection & Warning System
742:, pp. 33–34, David and Charles, 1973
7:
1013:Integrated Electronic Control Centre
459:Vertical colour light signal on the
293:One train working (with train staff)
58:adding citations to reliable sources
1275:Train automatic stopping controller
1195:Continuous Automatic Warning System
857:Two Centuries of Railway Signalling
955:Communications-based train control
691:"Railway Group Standard GK/RT0051"
25:
1625:Railway signalling block systems
540:improved capacity by about 50%.
168:In most situations, a system of
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1437:Westinghouse Brake & Signal
1200:ContrĂ´le de vitesse par balises
1066:North American railroad signals
276:, Great Eastern Railway, 1874;
45:needs additional citations for
1295:Transmission balise-locomotive
1260:Sistema Controllo Marcia Treno
1170:Automatische treinbeĂŻnvloeding
1056:Application of railway signals
876:Signalling in the Age of Steam
667:Kichenside & Williams 2008
550:Cooke and Wheatstone telegraph
1:
1245:Punktförmige Zugbeeinflussung
965:European Train Control System
718:Mylius, Andrew (2003-10-09).
1185:Chinese Train Control System
975:Radio Electronic Token Block
700:. p. D1. Archived from
602:Radio Electronic Token Block
266:Telegraph and Crossing Order
950:Centralized traffic control
592:Centralized traffic control
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1150:Automatic train protection
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378:Electric train staff (ETS)
352:Ordinary train staff (OTS)
344:Token (railway signalling)
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272:, Cornwall Railway, 1873;
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227:Strict timetable operation
138:A block instrument on the
1442:Westinghouse Rail Systems
1300:Transmission Voie-Machine
1145:Automatic train operation
1097:Track circuit interrupter
945:Automatic block signaling
940:Absolute block signalling
582:Absolute block signalling
536:, where upgrades for the
519:Global Positioning System
469:Automatic block signaling
451:Automatic block signaling
415:absolute block signalling
330:Accepting a token on the
307:One Engine in Steam (OES)
246:Timetable and train order
69:"Signalling block system"
1240:Pulse code cab signaling
1165:Automatic Warning System
1071:Railway semaphore signal
1033:Solid State Interlocking
632:Advanced Passenger Train
562:William Fothergill Cooke
239:railway being affected.
222:Block signalling methods
146:Signalling block systems
27:Railway signaling system
1140:Automatic train control
810:D. van Nostrand Company
1316:Level crossing signals
1235:Positive Train Control
1230:Linienzugbeeinflussung
960:Direct traffic control
597:Direct traffic control
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161:, and in Australia as
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1038:Westlock Interlocking
1028:Rail operating centre
990:Train order operation
985:Track Warrant Control
846:Hinson, John (2020).
612:Train order operation
558:North Midland Railway
552:was installed in the
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252:Train order operation
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1160:Automatic train stop
538:2012 Summer Olympics
506:moving block systems
504:fixed blocks. These
54:improve this article
738:Kieve, Jeffrey L.,
514:magnetic inductance
386:Manual block system
332:South Devon Railway
159:method of operation
157:, in the US as the
1000:Signalling control
924:Railway signalling
725:New Civil Engineer
534:London Underground
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461:Enshū Railway Line
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1422:Smith and Yardley
885:978-0-7110-3536-2
866:978-0-86093-672-5
832:(xvi+573+1 pages)
802:Klir, George JiĹ™Ă
669:, pp. 73–88.
554:Clay Cross Tunnel
288:One train working
155:method of working
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1309:Crossing signals
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179:route capacity
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1574:North America
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1451:Organisations
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1092:Track circuit
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932:Block systems
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819:0-442-24463-0
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607:Track warrant
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530:Northern line
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489:Moving blocks
488:
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479:rapid transit
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205:Basic concept
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71: –
70:
66:
65:Find sources:
59:
55:
49:
48:
43:This article
41:
37:
32:
31:
19:
1432:Union Switch
1336:Wayside horn
1180:Catch points
1087:Axle counter
1018:Interlocking
970:Moving block
931:
875:
856:
805:
796:
761:
755:
739:
734:
723:
713:
702:the original
697:
685:
674:
662:
650:
626:
570:single lines
565:
547:
526:Jubilee line
523:
510:
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498:
495:Moving block
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316:
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199:double track
195:single track
183:
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162:
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145:
144:
131:
116:
107:
97:
90:
83:
76:
64:
52:Please help
47:verification
44:
1594:Switzerland
1569:New Zealand
1564:Netherlands
1270:Slide fence
1023:Lever frame
785: [
655:Hinson 2020
338:Token block
300:train staff
163:safeworking
18:Safeworking
1502:By country
1285:Train stop
1250:RS4 Codici
1008:Block post
642:References
250:See also:
80:newspapers
1509:Australia
1362:AŽD Praha
1321:Crossbuck
1225:Crocodile
828:72-181095
748:655205099
270:Menheniot
110:July 2007
1619:Category
1599:Thailand
1407:Safetran
1397:Magnetic
1382:Griswold
1331:E-signal
576:See also
463:in Japan
408:(white).
278:Radstock
186:stations
150:railways
1544:Germany
1534:Finland
1519:Belgium
1514:Bavaria
1417:Siemens
1392:Hitachi
1367:Federal
1352:Adtranz
1255:SelTrac
1102:Treadle
1048:Signals
840:Sources
556:of the
544:History
532:on the
191:signals
170:signals
94:scholar
1589:Sweden
1584:Poland
1579:Norway
1549:Greece
1539:France
1524:Canada
1427:Thales
1357:Alstom
1326:Wigwag
1205:EBICAB
1175:Balise
882:
863:
826:
816:
746:
475:aspect
372:ticket
368:ticket
274:Thorpe
96:
89:
82:
75:
67:
1559:Japan
1554:Italy
1529:China
1463:AREMA
1412:Saxby
1265:SACEM
1210:IIATS
1135:ATACS
980:Token
789:]
705:(PDF)
694:(PDF)
618:Notes
101:JSTOR
87:books
1483:IRSE
1478:HMRI
1387:Hall
1130:ASFA
1125:ALSN
880:ISBN
861:ISBN
824:LCCN
814:ISBN
744:OCLC
528:and
73:news
1493:UIC
1473:FRA
1468:ERA
1458:AAR
1377:GRS
56:by
1621::
822:.
791:.)
787:de
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117:(
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108:(
98:·
91:·
84:·
77:·
50:.
20:)
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