In theory, trains are a Good Idea. They run on rails to a timetable so the driver doesn't have much opportunity to park up in a lay-by, have a sausage and a cup of tea and then go to sleep for half an hour (the usual reason why things on Earth don't work). Quite a surprise then that trains are usually late, uncomfortable, crowded or cancelled.

An interesting and curious social note: undercover government inspectors can often be seen on station platforms, photographing late trains and jotting down their details.