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Absolute Block Signalling
Absolute block signalling is a British signalling block system designed to ensure the safe operation of a railway by allowing only one train to occupy a defined section of track (block) at a time. Each block section is manually controlled by a signalman, who communicates with the other block sections via telegraph. This system was used on double or multiple lines where use of each line is assigned a direction of travel before the introduction of track circuits. A train approaching a section is ''offered'' by a signalman to his counterpart at the next signal box. If the section is clear, the latter ''accepts'' the train, and the first signalman may clear his signals to give permission for the train to enter the section. This communication traditionally takes place by bell codes and status indications transmitted over a simple telegraph wire circuit between signalmen using a device called a ''block instrument'', although some contemporary block working is operated wirelessly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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Signalling Block System
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, and the blocks are sized to allow a train to stop within them. That ensures that a train always has time to stop before getting dangerously close to another train on the same line. The block system is referred to in the UK as the ''method of working'', in the US as the ''method of operation'', and in Australia as ''safeworking''. In most situations, a system of signals is used to control the passage of trains between the blocks. When a train enters a block, signals at both ends change to indicate that the block is occupied, typically using red lamps or indicator flags. When a train first enters a block, the rear of the same train has not yet left the previous block, so both blocks are marked as occupied. That ensures there is sligh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |