Freight trains are thousands of feet long and haul unbelievably large quantities of material, the idea that it is inefficient to have a human (really a pair of humans) oversee and be responsible for a machine that large is laughable honestly.

…so is the idea that there is a genuine shortage of people willing to work as conductors, it is a convenient lie companies tell to rationalize why nobody wants to work for them because they pay shit and respect their employees so little that they won’t even give them unpaid time for necessary doctors appointments.

This point is even more true for passenger trains.