OMG this is *Really* impressive!!!
View Swiss trains live on a map : http://www.swisstrains.ch
Current version use Google Maps and the official train timetable to estimate trains positions, but they are working on a solution based on realtime GPS information...
Check the Follow feature : click on a moving train, click in the unfolding menu on the button "Follow". This will show you the moving train on a bird's eye view via satellite images!!