My wife and I are flying into Milan in a few weeks for a bike tour. We'll have 4 days on our own before we need to be in Venice for the start of our tour. How difficult will it be to travel to Siena with bikes? I'm thinking of Siena as a home base to visit other sites by way of day trips.
Here is a link to a page on the Trenitalia site that should answer your questions: http://tinyurl.com/2zugxq. After you go there, click on "Bicycle transport."
Darik, just check the trains for bike cars. They are listed on the schedule boards, (there will be a picture of a bike on a train car, showing the car #) plus you can ask when you buy your tickets. It will cost you a bit more to transport the bike on the train, just make sure you take it to the correct car (usually on the front or back of the train)
If your bikes are in a case/bag, you can just take it in the car with you as luggage. If it's put together, it will have to go into the bike car on the train.
It's very easy to travel via train with a bike in Italy - it's a very bike friendly country!