Neither train is permitted to move before the other has arrived. When trains run in opposite directions on a single-track railway, meeting points ("meets") are scheduled, at which each train must wait for the other at a passing place. Trains may only run on each track section at a scheduled time, during which they have 'possession' and no other train may use the same section. Every train crew understands and adheres to a fixed schedule.
The simplest form of operation, at least in terms of equipment, is to run the system according to a timetable. 5.3 Route signalling and speed signalling.2.2 Entering and leaving a manually controlled block.Wayside signalling dates back as far as 1832, and used elevated flags or balls that could be seen from afar. Foggy and poor-visibility conditions later gave rise to flags and lanterns. Hand and arm signals were used to direct the "train drivers". A mounted flagman on a horse preceded some early trains. The earliest rail cars were hauled by horses or mules. Not all these methods require the use of physical signals, and some systems are specific to single track railways. The set of rules and the physical equipment used to accomplish this determine what is known as the method of working (UK), method of operation (US) or safeworking (Aus.). a signalman or stationmaster) to the train crew. Most forms of train control involve movement authority being passed from those responsible for each section of a rail network (e.g. In the UK, the Regulation of Railways Act 1889 introduced a series of requirements on matters such as the implementation of interlocked block signalling and other safety measures as a direct result of the Armagh rail disaster in that year. This susceptibility is exacerbated by the enormous weight and inertia of a train, which makes it difficult to quickly stop when encountering an obstacle. Trains move on fixed rails, making them uniquely susceptible to collision. Railway signalling ( BE), also spelled railroad signaling ( AE), is a system used to direct railway traffic and keep trains clear of each other at all times. A Class 66 locomotive (right) is waiting at a red signal while a First Great Western passenger train (left) crosses its path at a junction.