I have travelled extensively in Switzerland by train and can heartily recomend visitors to Switzerland use it's excellent train system.

Most recently I have travelled the entire length of the Glacier Express (http://www.glacierexpress.ch/) which is a fantastic journey through the Swiss Alps. Also the section of the Voralpen Express between Rapperswil and Luzern is excellent through.

Of course, the Swiss Railway System runs many scenic tours (http://www.rail.ch/pv/sts-pano_e.htm) and I am informed that the William Tell Express is excellent although I have never used it myself.

Mark Sukhija, in London