Frankenbahn
In the mid-1920s Deutsche Reichsbahn further upgraded the line: the bridges were reinforced to increase permissible axle loads. Furthermore, additional passing tracks were built. On 20 December 1939, the Mosbach connecting curve ("Mosbacher Verbindungsbogen") was opened in Neckarelz between the Neckar Valley Railway from the south and the line to Osterburken. This relieved congestion on the Lower Jagst Railway (the section of the Franconia Railway between Bad Friedrichshall-Jagstfeld and Osterburken) created by the operation of "Iko-Verkehr" (a contraction of “Italy coal transport”) trains.