In signaling, what is a block?

• A. The section of track allocated for a train to occupy.
• B. A type of signaling device.
• C. A substation feeder line.
• D. A turnout control.

Answer: (A)

A block is the section of track allocated for a train to occupy. In block signaling, the route is divided into these blocks and a train is allowed to occupy one block at a time, with occupancy detected and shown at signals ahead to prevent entering a block that isn’t clear. This arrangement provides safe spacing and predictable movements by ensuring only one train occupies a given block until it moves on. The other terms describe different things: a signaling device refers to a signal or interlocking mechanism, not the track segment itself; a substation feeder line supplies power to the track circuits or electrified rails; a turnout control governs the movement of switches. The block concept is specifically about the length of track and its occupancy status to manage train separation.