I'd be interested to see how they intend to make this plan successful, then. There's no other avenue for the rail to collect revenue in that case, unless its economic benefit is already a significant net profit for the government. It may be, for all I know, it allows higher population density and encourages market participation, both of which increase taxes collected.

It is hard to see how it'll really convince many people not already taking public transit to use it, though. Cars are pretty expensive to have anywhere in Europe with the price of gas and typically more discouraging laws for car ownership (not sure what they're like specifically in Germany), I can't imagine it's a large cross-section of the population that drives because it's cheaper.