The Train Guy's video: 19th Century Token Exchange Signalling System in The UK Great Western Railways 2022

In railway signalling, a token is a physical object which a train driver is required to have or see before entering onto a particular section of single track. The token is clearly endorsed with the names of the section it belongs to. A token system is more commonly used for single lines because of the greater risk of collision in the event of a mistake being made by a signaller or traincrew, than on double lines. Location : Crediton, Devon Shire Route - Exeter St David's - Barnstaple / Okehampton Crediton station was constructed a few years before the first train was operated in India. Read more about this route at https://en.wikipedia.org/wiki/Tarka_Line The token system was developed in Britain in the 19th century, to enable safe working of single-line railways. For the very first time this system was proposed by Mr. Henry Woodhouse for Standedge Tunnels in 1849. If a 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. One Train Only token used by Indian Railways For convenience in passing it from hand to hand, the token was often in the form of a staff, typically 800 mm (31 in) long and 40 mm (1.6 in) diameter, and is referred to as a train staff. Such a staff is usually literally a wooden staff with a brass plate stating the two signal boxes between which it is valid. In UK terminology, this method of working on simple branch lines was originally referred to as One Engine in Steam (OES), and later One-Train Working (OTW). However the system was used on long through lines as well; R H Dutton, Chairman of the London and South Western Railway explained in 1876 the slow journey time between Exeter and Plymouth by saying, "the cause of the delay is the stopping at every station on the staff system. That really does cause a great delay because if the staff is not there, the train must stop while a man is sent on a horse to get it [from the other end of the section]"; quoted in Williams Using only a single token does not provide convenient operation when consecutive trains are to be worked in the same direction. The simple token system 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 followed). The driver was given a written authority to enter the single line section, referred to as the ticket. They could then proceed, and a second train could follow. In the earliest days the second train could proceed after a designated time interval, as on double lines at the time. However, following the Armagh rail disaster of 1889, block working became mandatory.