The Atlantic Citylab blog today had a good item explaining why London's transport system has the best finances, and how other transport systems can learn from them:
In U.S. cities, politicians often defer fare increases until there's a funding crisis too big to ignore. That leaves a bad taste in everyone's mouth about the transit agency's ability to manage its finances. It also leads city residents to believe that fare hikes are only something that should rarely occur.
In London, on the contrary, TfL fares rise every year—the only question is by how much. There are loud objections over there just as there are here, but the critical difference is that TfL has set an expectation in the minds of travelers, not to mention politicians, that fares must rise on an annual basis to meet costs. "That's the way we keep the system properly funded year after year," says [Shashi Verma, TfL's director of customer experience].
Other improvements, like pay-as-you-go travel cards (TfL's Oyster and Chicago's Ventra), could also find their ways over to the U.S.