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.
When you have a car, but you don't have a transit pass, the cost of completing a particular trip by car is (or at least appears to be) cheaper than doing so by public transit. For example, if I have to go to the city center and back by tram, the cost for two one-way tickets is € 4,60. The cost of one liter of gasoline is somewhere below € 2,00. Public transit only becomes cheaper than going by car if you use it regularly and thus purchase monthly or yearly passes.
