UKC

What's the best way to but tickets for impromptu train journeys around Europe, (Switzerland, Austria, Italy)?

Is there a recommended online resource for finding the best fares etc?

Have a look at The Man in Seat 61 and see whether he recommends anything:

https://www.seat61.com/

Edit - load of information here: https://www.seat61.com/Europe-train-tickets.htm

loco2.com is a good booking site, but if it's that impromptu just buy at the station, walk-up fares are not that expensive in any of those countries.

I’ve used loco2.com for longer trips in France and Spain, I’ve also bought tickets at the station on the day for shorter trips in both countries. I’ve bought on the day in Switzerland for long and short trips and it wasn’t much more expensive.