We need to get from Varenna to Tirano to catch the Bernina Express to St Mortitz. Where do I go to book my tickets?
The train is a Regionale, therefore no reservations required or available. That being said, there is no ticket office at the station or ticket vending machine. They are sold at a travel agency in Varenna and at a Tabac.
You can also buy tickets in Milan if you will be there first. The ticket must be validated before you board the train, that is what activates the ticket.
They can also be bought on-line at www.trenord.it, but they must be used in a 4 hour time window (or there about), so they are more restricted than tickets bought out of vending machines, which are good for several months or until validated.
Cindy,
You can buy your tickets in Milan prior to going to Varenna or at the helpful Tivano Tours office, which I believe is now located in the station in Varenna. As that's a Regionale train, DON'T forget to validate your ticket prior to boarding the train on the day of travel, or you'll risk hefty fines! You can view the schedules on the Trenitalia website.