What kind of operation is indicated by the term 'Block Signal'?

The term 'Block Signal' refers specifically to a fixed signal that governs a train's entry into a block section of track. Block signals are essential for safe railroad operation, as they help to prevent collisions between trains by providing clear indications about whether a track section is occupied or clear. When the block signal is set to 'stop,' it informs the train that they cannot enter that section of the track, typically because another train is already using it or the section is otherwise not safe for entry. This mechanism is fundamental to maintaining safe distances between trains, thereby ensuring orderly flow and minimizing the risk of accidents.

The fixed aspect of block signals provides consistency and reliability in train operations, as train crews can always rely on these signals to convey critical information about the state of the track ahead. This allows for a structured and regulated train movement system.