As of June 1, 2016, it has officially been “full steam ahead” for the longest rail tunnel in the world. The 57-kilometer Gotthard Base Tunnel in Switzerland, a once-in-a-century undertaking that has taken 17 years to complete, provides an important rail link between railway stations across Europe. One of the major challenges was to make the tracks accessible to the diesel-run emergency vehicles at all times. Even during construction work, uninterrupted operation of the tracks is crucial. This means that it must be possible to short-circuit the traction power supply cables safely and conveniently without closing off the route. PFISTERER developed an innovative earthing and short-circuit device that is installed on the ceiling, providing unobstructed access. This solution uses a torque-controlled, removable earthing pole equipped with retaining brackets to short-circuit the feeder conductor that runs along the ceiling. The terminals can be positioned and screwed into place with pinpoint precision and, in the interests of safety, the earthing pole cannot be removed until a certain level of torque has been reached.
The earthing and short-circuit device is also extremely durable. External measurements have shown that the terminals are able to withstand a maximum short-circuit current of 40 kA/100 ms without moving.