Here's a thought - rather than checking tickets on train and at station exit, why not simply charge people to get onto the platform, and it's then up to them to get off on whichever other network platform they like.
"It wouldn't work BECAUSE" ... I hear you say. Yet in works on the New York Subway and on the PATH, where I was at the tail end of last week. Looking and learning as part of our 'holiday' trip - and seeing some very different systems and perhaps picking up one or two ideas, and a few hundred pieces of knowledge.
Take a look at
http://www.wellho.net/mouth/4486_.html for my Newark Travelogue - posted into "Fares" because much of my confusion and issue was with their fare system. Some things are the same the world over!
Just to give you a flavour ...
