Automatic block signaling
RAILROAD COMMUNICATIONS SYSTEM
Automatic block signalling; Automatic block signal; Automatic Block Signal; Automatic Block System; Automatic Block Signaling
Automatic block signaling (ABS), spelled automatic block signalling or called track circuit block (TCB ) 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 blocks using automatic signals.