Since the opening of the Wemmetsweiler curve in 2003, the line branches west to Lebach as the Prims Valley Railway (Primstalbahn) and east to Neunkirchen.

Initially it was planned that the coal mines would be connected with branch lines to the Sulzbach valley.

For this reason it was decided in 1866 to build a line from Neunkirchen to Saarbrücken via the Fischbach valley.

Following the closure of the Göttelborn mine, the Merchweiler–Göttelborn branch line continues to be used to operate to the Weiher power station.

The bridge of state road L 128 over the line in Wemmetsweiler was replaced during urban redevelopment by a 54 metre long railway tunnel.