What is the MINIMUM number of train crews required to maintain a ten-minute headway on a line with a scheduled round time of one hour?

To calculate the minimum number of train crews required to maintain a ten-minute headway on a line with a scheduled round trip time of one hour, it's essential to consider both the travel time and the frequency of service.

The total time for a round trip is one hour, which translates to 60 minutes. When a train operates with a headway of ten minutes, it means that a new train must depart every ten minutes. In one hour, you can fit six ten-minute intervals (60 minutes divided by 10 minutes per interval). Therefore, six trains are required to ensure a train is dispatched every ten minutes.

However, it's important to account for the crews needed. Once a crew finishes their shift with one train, they cannot immediately operate another without an adequate break or turnaround time, leading to the need for additional crews. While the calculated trains for operation total six, you would need an extra crew to account for the ongoing operations and coverage during any delays or situation requiring an alternate crew, which leads to a total of at least six crews in rotation. The correct answer thus reflects the necessity for a total of six crews to maintain consistent service reliability while following operational protocols, including crew rest.

This systemic approach ensures that you have sufficient coverage to adhere to