How long must train doors be fully opened before they can be closed in the station?

The requirement for train doors to remain fully opened for a specified duration before they can be closed is primarily to ensure passenger safety. A ten-second wait allows passengers sufficient time to enter or exit the train comfortably, minimizing the risk of accidents or injuries that could occur if doors were to close too quickly. This duration is a standard safety measure adopted in the industry, which balances efficiency in train operations with the need to maintain a secure and welcoming environment for passengers.

While options like five seconds might be considered too short for adequate boarding and alighting, fifteen and twenty seconds could lead to operational delays, reducing the overall efficiency of train schedules. Thus, the ten-second requirement is a well-established practice to ensure that safety and efficiency coexist in train operations.