question regarding trains

Most "S-Bahn" or Schnell-Bahn are operated by German Rail, and, therefore, the German Rail Pass is valid on those trains. In some places, Berlin, I think, some of the S-Bahns are not operated by DB and the German Rail pass might not be valid (I not sure this is any longer the case, but check). Some towns, like Karlsruhe, operate Stadt-Bahnen (actually large streetcars), which they also call S-Bahn(s), but the German Rail pass would not be valid.

If you haven't already bought your passes, look at using Schönes-Wochenende- and Länder-Tickets for local travel on regional trains. The S-W-Ticket is valid for all transport in many cities (see here) and the Länder tickets (like the Bayern-Tickets) are usually valid for all transport in the transit districts (Verkehrverbünde) in that state.

For longer distance travel on express trains (ICE/IC/EC), if you purchase them in advance online from the Bahn, you can get Dauer-Spezial tickets for as little as €29 per person. A Dauer-Spezial ticket must include at least one leg on an express train, but will also include travel to/from the express train by regional trains.

I'm not sure what Barry is trying to say. If you are traveling within a metro district (Verkehrverbund), such as Munich's MVV, it doesn't matter whether you use regional trains or S-Bahns (S-Bahnen) within the district; you must "use" a day of your German Rail pass. You won't lose an extra day by taking an S-Bahn rather than a regional train.

However, it is usually less expensive to use point-point and "day" tickets from the district rather than a day of your pass.

And, only regional trains and S-Bahns are covered. No other mode of transport (Long distance trains, U-Bahn, streetcars, or buses) is covered.

If traveling outside a Verkehrsverbund, but still inside a single German Land (state), one of the Länder tickets (z.B. Bayern-Ticket) includes travel in the Verkehrsverbünde in the Land and is usually less than a day of your railpass.

only on regional trains in german cities. if you use s-bahns you willm lose a day on you pass.

only on regional trains in german cities. if you use s-bahns you will lose a day on you pass. u-bahns are not included.