block signal

listen to the pronunciation of block signal
English - English
The signal is often so coupled with a switch that act of opening or closing the switch operates the signal also
A fixed signal at the entrance to a block to govern a train or engine entering or using that block
A signal, that indicates, if the way after it is free Than it's green otherwise it's red
One of the danger signals or safety signals which guide the movement of trains in a block system
A fixed signal displayed to trains at the entrance of a block to govern use of that block
A fixed signal at the entrance to a railroad block, indicating whether or not trains may enter