The Strasbourg - Sarrebourg line is a reasonably busy double-track railway, electrified at 25kV AC. It crosses the Vosges via the Saverne Gap, the narrow twisting valley of the River Zorn that provides a relatively easy route through the mountains for the railway and the parallel Rhine - Marne Canal.
Passenger services were a mixture of TGVs, loco hauled passengers, push-pull sets and EMUs at the time of my visits and there are freights hauled by a variety of locomotive types. The second phase of the LGV Est opened in 2016, bypassing the line through the Saverne Gap and removing the TGVs.