Visiting the Grimsel Test Site (GTS)

Visitors at the GTS

Groups are welcome to visit from Tuesday to Friday. The Test Site is also open for group visits on occasional Saturdays.

Visits are possible from the middle of June to the middle of October. The tour of the facilities takes around 2 hours and is free of charge. The visit to the crystal cave (see The Crystal Caves at the GTS)  takes an additional 30 minutes.

Contact / Registration:

Renate Spitznagel
Hardstrasse 73
CH 5430
Tel + 41 (0)56 437 1282
Fax + 41 (0)56 437 1296
This email address is being protected from spambots. You need JavaScript enabled to view it.

"Visitor application" form

  • Following agreement of a visit date, this form should to be sent to the contact address in Wettingen at least six weeks prior to this date.

Confirmation of visit

  • You will receive a written confirmation from us approximately 4 weeks prior to the date of your visit.

Visitor list

  • The visitor list should be sent to the contact address in Wettingen at least 14 days prior to the date of the visit.

Arrival and departure

  • Visitors are responsible themselves for arranging transport to and from the agreed meeting-point. The meeting-point for visitors and the guide is generally Gerstenegg (cable-car station of Kraftwerke Oberhasli (KWO) AG). Reference should be made to the situation plan below.
  • Groups of more than 10 people should attempt, wherever possible, to arrive by bus (coach). Access to the tunnel is not possible with double-decker buses (maximum permissible vehicle height is 3.70 m).
  • For organisational reasons, we would ask you to arrive punctually. In the case of late arrival, we may be obliged to shorten or cancel the visit to the Test Site.
  • In the event of bad weather conditions - particularly later in the season (October) - the road over the Grimsel pass may close. Following prior agreement, the meeting-point will then be the Handeck cable-car station (see situation plan). It is possible in case of extreme weather that the visit may have to be cancelled at short notice for safety reasons.

Arrival at Gerstenegg

  • On arrival at Gerstenegg, the group leader is requested to make telephone contact with the GTS. The telephone is located to the right of the tunnel entrance in a box marked "Anmeldung". The telephone number is noted on the inside of the door of the telephone box.


  • The visit to the GTS lasts approximately 2 hours. A visit to the crystal cave takes an extra ½ hour. If the group is intending to visit the Kraftwerke Oberhasli (KWO), a visit to the crystal cave can be combined with this.
  • The visit to the GTS is free of charge.
  • There is a general ban on smoking in the GTS.
  • During the tour around the Test Site, the group must stay together.
  • Sensible footware is recommended.
  • The temperature in the tunnel is approx. 14°C and suitably warm clothing is recommended.

Situation plan

Travel guide for the Grimsel Test Site


The GTS underground facilities are also available to interested 3rd parties for underground testing and research. The GTS offers cost-effective access to a fully developed, well characterised underground research facility with round the year logistical support - please contact Dr. Ingo Blechschmidt, Head of the Grimsel Test Site, for further details.
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