Gotthard Base tunnel (GBT) – Electric power supply 50 Hz

Design of the 50 Hz medium- and low-voltage power supply with protection and control technology for the 57 km long twin-tube railway tunnel, comprising five feeding points for three electricity companies between Erstfeld and Bodio; Power grid analysis guaranteeing high safety, availability and redundancy requirements (RAMS); Review and ascertainment of aptitude of all installations under the severe ambient conditions (temperature and pressure); Coordination between energy consumers and suppliers as to service level, and with the civil works in terms of space needed for switching equipment, cable conduits and heat dissipation.

Main Data

  • 5 redundantly constructed grid coupling stations (6 and 10 MVA)
  • approx. 200 transformer stations (normal and auxillary net)
  • 10 no-break diesel generators (1000-1750 kVA)
  • approx. 200 low-voltage main distribu-tors incl. rapid switching modules
  • approx. 750 low-voltage sub-distributors
  • 3,200 km power cables (of which ap-prox. 360 km medium-voltage cables)
  • approx. 2,600 km fibre-optic cables
  • system protection technology
  • control technology for power supply


    AlpTransit Gotthard AG (ATG)


    IUB as 50 % partner of an engineering consortium

    Construction period


    Construction costs

    CHF 350 million

    Scope of services

    • Detail project incl. cost estimate
    • Coordination with civil works
    • Calls for tender (design & build)
    • Review of the working design
    • Supervision of implementation (shop inspections, prototype release, spot checks)
    • Preparation & monitoring of commissioning