Block #1 is occupied, signal into that Block is red. Block #2 is approached, thus showing yellow, other blocks are free, signals showing green.
Train Station with multiple Train stops and Rail signals to allow operation of multiple trains on single track.
Block #1 occupied, signal red. Block #2 approaching, showing yellow. Chain signal #3 is reflecting block signal #2. The chain signal #4 is showing red, because the block is to be approached from another direction, thus the block is considered occupied.
A simple test setup to start with. Containing Train stops for schedules, and Rail signals to watch their behaviour.