When the traffic direction has been set, the track circuits between stations are switched to transmit power opposite the train direction in order to ensure a continuous signaling system.
Fig. 2 Automatic block system (type A)
b Automatic block system (type B)
This system treats the block section between stations as a single block section, and is used on auxiliary trunk lines where there is relatively little traffic demand.
This system creates giant track circuits between stations but does not perform power transmission and reception switching. Therefore, in contrast to automatic block system type A, the signaling system is laid out in station units and uses distant signals.
Fig. 3 Automatic block system (type B)
c Special automatic block system (track circuit detection system)
This system was developed to modernize branch lines with low traffic volumes. The block section setting method and signaling system are the same as the automatic block system type B, but track circuits are not installed between stations and trains are detected instead.
