BLS Lötschberg Base Tunnel, Cavern Karst Water

Railway tunnels and underground construction

Project description 
In February and March 2020, the eastern tube of the Lötschberg Base Tunnel had to be temporarily closed because an unexpected water ingress washed sand into the tunnel. In order to ensure long-term rail operations, BLS remediated the damaged area in the eastern tube of the double-track section. In addition to the tunnel tube, BLS broke out a cavern and installed a settling basin with a capacity of over 2000 cubic meters. The mountain water now flows into this settling basin, any sand is allowed settle, and the purified mountain water flows to the Raron portal. If necessary, the accumulated sand will be transported out of the tunnel by rail car.

Due to the importance and urgency of the project, as well as the hindrance of the east tube closure, the entire scheduling was very tight. This required all the more accurate and coordinated planning and coordination, as well as efficient and goal-oriented cooperation between all parties involved. During the entire planning and procurement period from the end of September 2020 to the end of December 2020, as well as during execution and commissioning, a detailed schedule was kept for precise coordination and deadline control. This all made it possible to meet the milestones on time and not to slow down the rapid progression of the project.

Electrotechnical installations were begun on 25 January 2021. In just 3.5 weeks, hundreds of meters of cable paths, over 3 kilometers of various supply lines to the cavern, and over 9 kilometers of cables within the cavern were laid, as well as more than 1,800 wires were connected and more than 250 identification signs were attached. All these efforts made the approximately one-week commissioning phase possible, which was then successfully completed with an overall function and load test, so that on 26. February punctually at 12:00 the first commercial train could run through the east tube.

Our services
Comprehensive execution planning, as well as specialist construction management and commissioning of all electrotechnical equipment such as energy supply, low-voltage installations, control technology, data network, etc.

Pursuing the same goal together and pulling in the same direction is the key to success.

Owner / Reference
BLS Netz AG, Infrastructure – Installations & Projects – Civil Engineering
Martin Pfister IPMP

Client / Reference
Martin Pfister IPMP

Overall Planner / Reference
IG Karst, SRP Ingenieur AG
Peter Seiler

Project location / route
Lötschberg Base Tunnel
46,500 km

Planning services, project information


Railway tunnel, underground construction

SIA Phases
Execution Project – Commissioning

Planning time
End of 09/20 – end of 02/21

Technical Equipment
Energy Supply
Control and Signalling

Implementation time
End of 09/20 – end of 02/21

Under ongoing railway operations 
No (limited railway operation)

Construction costs
Electrical Equipment > CHF 1 million

Facts / Key figures
over 9 km of cables
more than 1,800 wires

Do you have any questions about this project?

We are happy to answer them – we want to inspire you with our planning services.

Contact Us

Alexander von Rütte
Phone +41 58 502 73 70
Contact by e-mail

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