In 2014 one passenger kilometer of travel with a DB long distance train emitted on average 11 grams of CO Deutsche Bahn operates the vast majority of German long distance trains and also sells tickets for regional and local trains operated by other companies.
The DB website (which has localized versions for many places and is available in English and a half dozen other languages) is an excellent resource to find train connections throughout Europe, although some heritage railways and railway integrated bus services are not listed.
A new timetable comes into effect each December, usually being published in mid October.
On most routes tickets can be booked up to 180 days ahead and if you know your itinerary this far ahead, it is advisable to book so early as there are next to no last minute offers and pre-booked tickets rise in price on a "first come first served" basis.
Bidding for a new contract usually starts before the old contract has run out.
Contract terms tend to be quite long: on some routes DB still operates under contracts that weren't subject to open bidding or where DB was the only bidder.
Germany's rail system is fast and reliable and covers most points of interest.However, most Germans don't book more than one week ahead, with the possible exception of international tickets.Germany has over 40,000 kilometers of railways (making it the sixth longest rail network and one of the densest worldwide) and thus is incredibly well-connected, making it possible to connect from most rural areas to large metropolises.A train journey from Hamburg in the north to Munich in the south will usually take less than 6 hours.The same journey by car takes around eight hours, a bus takes ten hours or more and neither of those figures accounts for traffic congestion.