On old British rail trains, commuter trains had many doors, I think on each side there was a door for each pair of row of seats? There was also no door lock, s

On old British rail trains, commuter trains had many doors, I think on each side there was a door for each pair of row of seats? There was also no door lock, so people could start leaving the train before it fully stopped. The lack of a door lock is also why they're not used anymore.