page_title: Flytoget
section_title: Challenges
hierarchical_section_title: Flytoget / History / Challenges
caption_attribution_description: Norsk bokmål: Lutvann i Oslo sett fra syd. English: The lake "Lutvann" in Oslo, Norway. Seen from the south.
context_page_description: Flytoget, the Airport Express Train is a Norwegian high-speed airport rail link connecting Oslo Airport, Gardermoen to Oslo Central Station in nineteen minutes. Run by Flytoget AS, it operates on the high-speed Gardermoen Line using sixteen GMB Class 71 electric trains. Normal service frequency is once every ten minutes, with five of the services each hour continuing westwards beyond Oslo Central. The extended services serve nine stops within Greater Oslo and take up to 60 minutes.
  Flytoget transported 5.4 million passengers in 2007, a 34-percent market share of airport ground transport. The service, which has a top speed of 210 kilometres per hour, is the only high-speed rail service in Norway. Construction started in 1994 and high-speed trains began serving Gardermoen Airport from the date of its opening on 8 October 1998, although full operation using the 14.5-kilometre-long Romerike Tunnel had to wait another ten and a half months after severe leaks caused by the tunnel's construction led to the partial depletion of two lakes.
  Formed in 1992 as a subsidiary of Norwegian State Railways, the company has been owned since 2001 by the Norwegian Ministry of Trade and Industry.
context_section_description: The greatest challenge was the need to build the 14,580-metre (47,830 ft) Romerike railway tunnel – Norway's longest – beneath the geologically highly unstable Østmarka area between Etterstad, close to Oslo Central Station, and Lillestrøm. During construction, in 1997, the water level in some lakes above the tunnel, including Lutvann and Nordre Puttjern, sank dramatically. After the leaks were discovered on 3 February 1997, sanctions were imposed by the Norwegian Water Resources and Energy Directorate requiring the elimination of all leakages. At its worst, the tunnel was leaking 3,000 litres (660 imp gal) of water per minute.
  Rhoca-Gil sealant was used in an attempt to fix the leaks, but failed to work properly. Not only did it not polymerise, and therefore failed to staunch the leaks, but it also poisoned its surroundings with acrylamide. Manual fixing with concrete became necessary; the fixing and cleaning up of the toxin delayed the building of the tunnel by one year. Further complications arose due to conflicts between NSB Gardermobanen and the construction company, Scandinavian Rock Group, with the latter at one instance stopping work for three weeks while the parties quarrelled in court.
  Reports have shown a lack of inspection and reporting procedures during incidents that should have been addressed – but were never taken seriously – in 1995. Construction of the tunnel caused damage to around sixty houses and an evaluation by the Ministry of Transport and Communications showed that NOK 500 million was spent on fixing the leaks and claimed that this was to a large extent an unnecessary expenditure which  more efficient engineering procedures would have avoided. The report also criticised the administrative planning and organisation of the overall construction of the railway.
  Airport Express Trains began operating as soon as the new airport (and the Lillestrøm to Gardermoen stretch of the new high-speed line) opened on 8 October 1998; however, for more than ten months they had to use the old Hovedbane (Trunk Line) between Oslo S and Lillestrøm, which restricted their frequency to just two trains per hour. Regular operations at full capacity, using the Romerike Tunnel, did not commence until 22 August 1999.
caption: Lake Lutvann was partially drained due to construction problems during the digging of the Romerike Tunnel
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