The fatal problem: the train is arriving in N minutes whether or not the car is ready. Just as car loading is to be finished (no more people allowed), the last

The fatal problem: the train is arriving in N minutes whether or not the car is ready. Just as car loading is to be finished (no more people allowed), the last person trips and falls, twisting an ankle. Do you have time to help them on board? How do you get them out of the way? If the car is not ready for whatever reason there is no fallback... that car has to attach or else there will be a collision. It seems far too rigid an approach to accept regular humans as a moving part.