The walls without doors (open at the door area) might be simple. But walls with doors does not seem as simple. If someone gets trapped between the doors, then

The walls without doors (open at the door area) might be simple. But walls with doors does not seem as simple. If someone gets trapped between the doors, then the train should be disabled from moving. You see it most often - people dashing in at the last moment getting themselves or their backpack getting stuck. The station doors also have to synchronize with the train doors. Else say, the train door opens, you step out but the station door does not open. Now the train is ready to move...