Parisian metro and RER are nice. Metro is just a silver handle you flip and I believe it locks while in movement (I haven't ridden long enough in Paris to be ab

Parisian metro and RER are nice. Metro is just a silver handle you flip and I believe it locks while in movement (I haven't ridden long enough in Paris to be able to see someone try to flip the handle when it moves). Sweden/Denmark do it a bit better even. Sweden/Denmark regional trains are just a button in the door that lights up when you can press to open (only when stopped). In Denmark the metro is all automated with the doors. They do also have the infuriating motion sensors for the middle of the trains though where you stand there like an idiot sometimes trying to trip it and end up having to wave your hand above your head to get it to open.