Cool, would they pay $5 extra?

We already have some of the most expensive trains in Europe. I don’t think this really a valid argument.

It's a valid argument regardless of the base price.

Machines are generally cheaper than people. People like saving money more than they like talking to people. If given the choice they will almost always choose the machine, when they have to pay the price.

You also have to figure in what the savings actually are. For the railways in England, the staff costs (all of them - from signallers to drivers, maintenance workers, cleaners, guards, ticket office staff) are 20% of the cost of running the railway. Getting rid of a relatively small number of the worst paid staff on the railway will not do much to reduce the cost of running the railway - certainly not £5 per ticket’s worth, and the very small overall savings will not get passed on to the customers anyway.

Getting rid of a relatively small number of the worst paid staff on the railway will

Still save a significant chunk of money because people are still very expensive and ticket staff work 24/7.

certainly not £5 per ticket’s worth, and the very small overall savings will not get passed on to the customers anyway.

They almost certainly will be in one form or another. Even if the railroad keeps every dime the extra productivity in the economy you get from people not working as ticket staff will lead to improvements across the board.