What is the purpose of the door relay in R-10 series cars and later?

The purpose of the door relay in R-10 series cars and later is to close the control circuit after all doors are closed. This function is crucial for ensuring safe train operations, as it allows the train's system to confirm that all doors are secured before the train can proceed. When the doors have successfully closed and the relay activates, it sends a signal that the train is safe to move, enhancing passenger safety by preventing accidental departures while doors are open, which could lead to dangerous situations.

This mechanism is integral to the train's operation, as it helps to establish a clear protocol for door management. It also contributes to the reliable functioning of the train’s systems, ensuring that safety measures are in place prior to departure.