In each Verkehrsverbund all public transport (this may include subways, city buses, S-Bahn, light rail and even regional trains) can be used with a common ticket and fare system.
On major lines, ICE or IC trains run as often as hourly during the day, and even some smaller cities popular with tourists like Tübingen or Heringsdorf have daily or weekly services.
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.
Rail travel in Germany has been nominated for featuring on the main page as Featured Travel Topic.
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