Cable drum wagon

From March to June 2021, Sersa provided logistical support to Studer Cables AG in the installation of two new 132 KV cable loops in the Zimmerberg base tunnel. The new Sdmmers cable drum vehicle was also used.

It transported up to four heavy cable drums that could be driven or braked during installation. In the Zimmerberg tunnel, two 132 kV cable sections were installed during every installation shift. The two 3.4 metre diameter cable drums weighed 20 tonnes each. 

The Sdmmrs twelve-axle low-loading freight wagon was originally used by the Austrian Federal Railways as a heavy haulage vehicle. Extensive modifications made it today's powerful cable drum run-out wagon. Four run-out stands with individual drives, an auxiliary generating set to supply electricity, various additional units and a shaft bearing were installed. Two specially trained employees operate the run-out stands, winches, etc.

The cable drum wagon is used in conjunction with a traction unit and an auxiliary wagon. A generator obviates the need for an external power supply. The installed lighting ensures safe operation in railway tunnels and at night. Emergency stop switches stop the motors immediately in the event of imminent danger. The maximum speed of the cable drum is 8.7 rotations/min., the laydown rate is 90 m/min. The vehicle can be used for dismantling and installation operations. The winding machine’s high pulling force (up to 5000 N) allows large-diameter or extremely long cables to be laid. 

This cable drum wagon, unique in Switzerland, was the ideal solution to the economic and technical requirements of the Swiss Federal Railways’ cable project in the Zimmerberg Base Tunnel. The cable drum wagon was the only option for laying two 1,300-metre-long cable sections in the short installation shifts.