Train conductors are valuable IF they have first aid and CPR training; maybe riot training. There are probably a few other things along those lines as well - but none of them have anything to do with running a train: all the train related tasks can be better done automated.

There are still some things in an airplane that an autopilot cannot do. There is nothing on a train in normal operation (as opposed to maintenance) that a computer cannot do - as evidenced by multiple trains around the world running without humans operators since the 1990s!