Advice for train from Zurich to siena in May?
It's long and boring: you need an IC train Zürich-Milano, then a high-speed Frecciarossa train Milano-Firenze, then a regional train to Siena. The whole thing will probably take 7h or so.
According to the timetables on the German Rail site, the fastest daytime route (8hr5min) is Zuerich-Milano-Firenze-Empoli-Siena. You can eliminate the connection in Empoli by waiting for a direct train from Firenze to Siena, but the trip will take half an hour longer. You also can travel overnight: Zuerich-Innsbruck-Firenze-Empoli-Siena in 14 hours with the Innsbruck-Firenze leg on a CNL night train.
Thank you both of you, much appreciated!
Joy, As the others mentioned, the shortest trip is 8H:05M with four changes. One of the longest is 9H:07M with only two changes. Despite the extra hour, I might consider the longer trip just for simplicity. I've taken similar trips with as many as five changes and although it's a FULL travel day, its tolerable. When you arrive in Siena, I'd suggest taking a Taxi from the station. Happy travels!