The Swiss railway system is famous for its quality and accuracy. In general, Swiss people use the train very often, even for their everyday transport. There are very frequent routes that connect the most important urban areas, but also some smaller communes.
The site of SBB CFF FFS (Swiss railway in 3 languages) provides information for the timeschedules, the prices and offers an online ticket shop. Ticket’s control is done using barcode reader, so you can print your ticket bougt online.
There is a very useful app for checking the timeschedules from your smartphone. If you sign in and add your credit card info, you can even buy your ticket inside the train.
If you use the train inside the Lausanne area and the suburbs, you can still use the mobilis card for the buses/metro. For example you can use your card that covers the zones 11 and 12 to take the train from Lauasanne-Gare to Renens-Gare.