Actually, fyi, the company that is responsible for most of the schedules and time tables is hacon, and the system they offer is called hafas. If you search for the term, you'll find that many, if not most, european transportation providers rely on them for their services. That's why I can search for a train in suburban france using my deutsche bahn-iphone app. it would only be a matter of understanding that one api and the data would be open ( without any screen-scraping or other hacks involved ).
A friend of mine started to reverse engineer the API, that the DB-Navigator App uses, as it covers pretty much every public transport in Germany and at least trains (and sometimes trams and buses) in all of Europe. It can even give you a route to Pjönyang, North Korea. I don't know how successful he has, though.
That guy somehow figured out how to get the data for a lot of cities, Cologne being one of them. Maybe he knows how to get it.