Headway is defined as the time or distance between successive trains; its significance in subway operations is

Headway is defined as the time or distance between successive trains; its significance in subway operations is

• A. The time a train spends at a station for boarding and safety checks.
• B. The time or distance between successive trains; critical for capacity and safe spacing.
• C. The distance a train travels from origin to destination in a trip.
• D. The duration of a complete line timetable.

Answer: (B)

Headway is the interval between successive trains. In subway operations this interval directly determines how much capacity a line can support and how safely trains must be spaced along the track. Short headways allow more trains per hour, increasing capacity, but they require precise signaling, reliable braking, and tight control of speeds and dwell times to maintain safe gaps. Longer headways reduce capacity but give more buffer for delays and variability, improving safety margins. The other ideas describe different measures: dwell time is how long a train spends at a station, trip distance is the distance from origin to destination, and timetable duration is the length of the service period. So the concept that links capacity and safe spacing is the headway—the time or distance between trains.

Headway is the interval between successive trains. In subway operations this interval directly determines how much capacity a line can support and how safely trains must be spaced along the track. Short headways allow more trains per hour, increasing capacity, but they require precise signaling, reliable braking, and tight control of speeds and dwell times to maintain safe gaps. Longer headways reduce capacity but give more buffer for delays and variability, improving safety margins. The other ideas describe different measures: dwell time is how long a train spends at a station, trip distance is the distance from origin to destination, and timetable duration is the length of the service period. So the concept that links capacity and safe spacing is the headway—the time or distance between trains.