Construction began in 1992, and the traffic opening was originally planned for 1995. However, construction was plagued by major difficulties concerning large amounts of water seeping in from surrounding rock, only a small fraction of which had been foreseen. Additionally, the original drill, which was said to drill 100 meters per week, broke down after drilling only . The rock was too soft, so the machine could not use it to pull itself forward. The contractor tried to drill traditionally, but had to spend a lot of effort on sealing the water leaks. The contractor went bankrupt and a new contractor, Skanska, was contracted. The new contractor had similar trouble but a better contract that gave compensation for troublesome rock conditions.