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Specially-made glued joints, where all the gaps are filled with epoxy resin, increase the strength again. As an alternative to the insulated joint, audio frequency track circuits can be employed using a tuned loop formed in approximately 20 m (66 ft) of the rail as part of the blocking circuit. Some insulated joints are unavoidable within turnouts.
The basic principle behind the track circuit lies in the connection of the two rails by the wheels and axle of locomotives and rolling stock to short an electrical circuit. This circuit is monitored by electrical equipment to detect the absence of the trains. Since this is a safety appliance, fail-safe operation is crucial.
Rail stressing. Stressing is a rail engineering process. It is used to prevent heat and cold tension after installation of continuous welded rail (CWR). Environmental heat causes CWR to expand and therefore can cause the fixed track to buckle. Environmental cold can lead to the contraction of the fixed railway track causing brittleness and cracks.
In Nazi Germany, a railway system with a 3,000 mm (9 ft 10 + 1 ⁄ 8 in) gauge width was planned. For this Breitspurbahn railway system, electrification with a voltage of 100 kV taken from a third rail was considered, in order to avoid damage to overhead wires from oversize rail-mounted anti-aircraft guns. However, such a power system would not ...
Double junction, or level junction (left hand running). A double junction is a railway junction where a double-track railway splits into two double track lines. Usually, one line is the main line and carries traffic through the junction at normal speed, while the other track is a branch line that carries traffic through the junction at reduced speed.
A railroad tie, crosstie (American English), railway tie (Canadian English) or railway sleeper (Australian and British English) is a rectangular support for the rails in railroad tracks. Usually laid perpendicular to the rails, ties transfer loads to the track ballast and subgrade, hold the rails upright and keep them spaced to the correct ...
Automatic block signaling. Automatic block signaling (ABS), spelled automatic block signalling or called track circuit block (TCB[1]) in the UK, is a railroad communications system that consists of a series of signals that divide a railway line into a series of sections, called blocks. The system controls the movement of trains between the ...
A block instrument on the Midland Railway. Signalling block systems enable the safe and efficient operation of railways 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, [1] and the blocks are sized to allow a train to ...