I'm looking into the cheapest rail route between Mulhouse and Stuttgart for a trip next spring. I'm specifically wanting to find out whether a Baden-Wuerttemberg Ticket covers local Ortenau S-Bahn trains from Strasbourg into Germany. According to the DB website, the Baden Ticket covers OSB services in general, but it doesn't specifically say whether it covers cross-border trains or not. Does anyone here know, or will I need to contact OSB?
The official map showing the validity of the Baden-Württemberg ticket is here.
It does cover some cross-border routes, but in this case it only runs up to Kehl, the last station across the river Rhine before Strasbourg. It is not valid from Strasbourg to Kehl.
But, there is another route from Mulhouse to Stuttgart. If you look at the map there is a direct service from Mulhouse to Müllheim, and then to Freiburg. In this case you would need to buy a ticket from Mulhouse to Neuenburg, and use the Baden-Württemberg ticket from there.
But, But, a Baden-Württemberg ticket is only valid on regional trains, not on IC or ICE, and Mon-Fri only valid from 09:00 (Weekends valid all day). If you buy your ticket in advance you can save a lot of money on a normal ticket which is valid on IC/ICE. Mulhouse - Stuttgart will take about 3½ hours by IC/ICE, and 4½ to 5 by regional trains.
Thanks very much for pointing out that link from Mulhouse to Muellheim. According to the DB website, the walk-up single ticket is only about six euros.