Replacement frequency converter Lötschberg Base Tunnel

Railway tunnel Technical facilities / equipment

Project description
BLS Netz AG has been operating and maintaining the 34.6km long Lötschberg Base Tunnel since it went into operation in 2007. The tunnel has three ventilation units of 2 high-performance axial fans each, which are driven by frequency converters. The motors of the fans have nominal operating capacities in the range between 500 and 1,500 kW, which are supplied with electrical energy by their own medium-voltage transformers. These facilities are used for the operation and maintenance of the Lötschberg Base Tunnel, in normal and incident operation.

EPRO TRAFFIC was commissioned to design and accompany the replacement of the frequency converters that drive the axial fans’ motors. For this purpose, an inventory including on-site inspection was carried out in a first phase, which defined the framework conditions for the preparation of procurement documents. EPRO TRAFFIC supports BLS Netz AG with the preparation and elaboration of technical specifications and the development of the tender’s commercial part. This defines both the criteria for awarding the contract and the technical requirements for the new installations.

After the procurement of the new frequency converters, the implementation planning or the elaboration of the production project is carried out by the manufacturer / supplier. In this phase, EPRO TRAFFIC carries out specialist controlling in coordination with the previously created functional specification and the requirements for the new systems contained therein. The development of test criteria for the factory acceptance test is carried out in close coordination with the tunnel’s existing operating criteria.

After production of the systems, EPRO TRAFFIC will work in close cooperation with all parties involved to develop a script for the installation and commissioning process. This ensures smooth installation during ongoing operation of the tunnel. After the test criteria for commissioning have been defined, the individual machines are gradually installed and put into operation.

Our services
Documentation on site, preparation of technical and commercial tenders, support of public procurement procedures, specialist controlling and owner representation during production, elaboration of criteria and support during the factory acceptance test, development of script for installation and IBS, support for installation and commission, examination of delivery documentation and acceptance

Owner / Reference 
Installations & Projects, IPHG Low Voltage

Client / Reference 
Rolf Fankhauser, IPHG Low Voltage

Project location / route
Lötschberg Base Tunnel

Planning services, project information



SIA Phases
Construction Project – Commissioning

Planning period
2017 – 2019

Technical installations and equipment

Implementation period
2017 – 2019

Under ongoing railway operations 

Construction costs
CHF 3.5 million

Facts / Key figures 
3 ventilation units of 2 high-performance axial fans each with 500–1500kW

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Contact Us

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

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