Rule 55 was an operating rule which applied on

British railways British Railways (BR), which from 1965 traded as British Rail, was a state-owned company that operated most rail transport in Great Britain from 1948 to 1997. Originally a trading brand of the Railway Executive of the British Transport Commis ...

in the 19th and 20th centuries. It was superseded by the modular rulebook following re- privatisation of the railways. It survives, very differently named: the driver of a train waiting at a signal on a running line must remind the signaller of its presence. Signal box inside

Rule 55 was introduced following a spate of accidents caused by signalmen forgetting that trains were standing on a running line, sometimes within sight of their

signal box A signal is both the process and the result of transmission of data over some media accomplished by embedding some variation. Signals are important in multiple subject fields including signal processing, information theory and biology. In ...

es. It required that, if a

train A train (from Old French , from Latin">-4; we might wonder whether there's a point at which it's appropriate to talk of the beginnings of French, that is, when it wa ... , from Latin , "to pull, to draw") is a series of connected vehicles th ...

was brought to a stand at a signal, within three minutes in clear weather or immediately in rain, snow, or fog, the driver of the train must despatch his

fireman A firefighter (or fire fighter or fireman) is a first responder trained in specific emergency response such as firefighting, primarily to control and extinguish fires and respond to emergencies such as hazardous material incidents, medical in ...

guard Guard or guards may refer to: Professional occupations * Bodyguard, who protects an individual from personal assault * Crossing guard, who stops traffic so pedestrians can cross the street * Lifeguard, who rescues people from drowning * Prison gu ...

, or any shunter riding on the train, to the signal box to ensure that the signalman was aware of the presence of the train, and that all safeguards to protect it, such as slides or collars on the signal levers, were in place, the crewman then signing the train register to confirm this. In practice, this meant a cautious trudge, in whatever weather, for the crewman. Occasionally the rule was obeyed to the following extent: the crewman merely exchanged a greeting with the signalman, signed the register and returned to the train. In many cases, such as at major junctions or marshalling yards where crewmen crossing the rails were in grave danger from moving trains, the rule could not be applied properly (see exemption white diamond pictured). Further, the need for the fireman to return to the train would delay it if the signal was cleared in the meantime.

Accidents

Failure to apply the rule properly was a factor in several railway accidents in the period from 1890 onwards. At

Thirsk Thirsk is a market town and civil parish in North Yorkshire, England; it is known for its racecourse and depiction as local author James Herriot's fictional Darrowby. History Archeological finds indicate there was a settlement in Thirsk aro ...

and Hawes Junction, the crews of the standing trains failed to carry out the rule. At Quintinshill, the fireman of the standing train signed the register but did not ensure that the signalman had put the necessary safeguards in place. Diamond sign

It is impossible to know precisely how many accidents were prevented by the proper observation of the rule, and it could not always prevent a crash. At Winwick, a train was brought to a stand some distance from the signal box. The fireman left promptly to carry out the rule, but he had not reached the signal box before his train was struck. To prevent such occurrences, 'call plungers' (which operate an indicator in the signal box when pressed) or telephones were installed at some signal posts, or

track circuit A track circuit is an electrical device used to prove the absence of a train on a block of rail tracks to control railway signals. An alternative to track circuits are axle counters. Principles and operation The basic principle behind the t ...

s installed. However, even this solution was not completely foolproof e.g. at

Castlecary Castlecary () is a small historic village in North Lanarkshire, Scotland, directly adjacent to the border with Falkirk Council, Falkirk. It has long been associated with infrastructure, being adjacent to Red Burn, a bridged river, a Castra, Roma ...

in 1937, the signalman observed that a train had

passed a signal at danger A signal passed at danger (SPAD) is an event on a railway where a train passes a stop signal without authority. This is also known as running a red, in the United States as a stop signal overrun (SSO) and in Canada as passing a stop signal. SP ...

, possibly due to a false signal indication, and assumed it had continued on past his signal box. The signalman failed to check his track circuit indicators, which would have shown that the train stopped, and the fireman arrived in the signal box moments too late to stop the signalman accepting a following express train. Full

interlocking In railway signalling, an interlocking is an arrangement of signal apparatus that prevents conflicting movements through an arrangement of tracks such as junctions or crossings. In North America, a set of signalling appliances and tracks inte ...

with track circuits and signal indications might have prevented this accident.

Exemption

A white diamond sign on a signal post means that the driver is not required to contact the signaller because a telephone is not provided, but the presence of the train or shunting movement is indicated to the signaller by

detection {{Unreferenced, date=March 2018 In general, detection is the action of accessing information without specific cooperation from with the sender. In the history of radio communications, the term "detector" was first used for a device that detected ...

Modernised rule

The principle of Rule 55 continues – though from 2003 (and as of 2019) the rule is identified rather differently. Rule Book (GE/RT8000) Module S4 ''Trains or shunting movements detained on running lines'', Section 1 (''Contacting the signaller - standard arrangements''), revised 2015, states (1.1 ''When to contact the signaller''): Modern technology such as signal post telephones, in-cab radio, and mobile phones means that it is rarely necessary for train crew to visit the signal box. In fact, the driver does not even need to speak to the signaller as pressing the "SG" button on CSR and

GSM-R GSM-R, Global System for Mobile Communications – Railway or GSM-Railway is an international wireless communications standard for railway communication and applications. A sub-system of European Rail Traffic Management System (ERTMS), it is use ...

radios will send a "Train standing at signal" text message.

Accidents

Exemption

Modernised rule

References

Further reading