What is the Absolute Block System of train working?
‘Absolute Block’ refers to a system where the the track is considered to consist of a series of sections, such that when one train is occupying a section of track (the block section), no other train is allowed to enter that section. In addition, no train can enter an empty block section without first securing the permission of the station in advance. This is the most widely used system for ordinary train routes. A station or signalbox controls a block section in one direction (from its rear), and no train may enter that block in that direction without permission from that signalbox (the station or signalbox is said to accept or receive the train). When a train has been accepted, no other trains can be accepted on that block section until it has left that block section. Obviously the two signalboxes at either end of the block section have to tightly coordinate their actions, especially in the case of block sections that allow bidirectional movement on a single line. The permission to en
