Rail transport operations

The operation of the railway is through a system of control, originally by mechanical means, but nowadays more usually electronic and computerized.Signalling systems used to control the movement of traffic may be either of fixed block or moving block variety.Most blocks are 'fixed' blocks, i.e. they delineate a section of track between two defined points. On timetable, train order, and token-based systems, blocks usually start and end at selected stations. On signalling-based systems, blocks usually start and end at signals. Alternatively, cab signalling may be in use.