The contract was awarded by Rhine-Main Transport Association (RMV) together with the state of Baden-Württemberg and the Rhine-Neckar Transport Association.
The services will be operated with new three and four-car Twindexx EMUs to be built by Bombardier. Two four-car trains will operate at peak times offering around 800 seats. The new EMUs will replace older locomotive-powered double-deck push-pull trains.
One service will operate over the Main-Neckar line from Frankfurt via Darmstadt and Weinheim to Heidelberg and Mannheim, while the other will run over the Riedbahn from Frankfurt via Biblis to Mannheim.