On the topic of Swedish tunnels there's the one through Hallandsås, where three (?) different construction companies tried. Several tunnel boring machines got s

On the topic of Swedish tunnels there's the one through Hallandsås, where three (?) different construction companies tried. Several tunnel boring machines got stuck in the soft rock, cows died from water poisoning, and the whole thing was delayed more than 100% of the estimated project time. Fascinating story. > Additionally, the original drill, which was said to drill 100 meters per week, broke down after drilling only 18 m (59 ft). 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. https://en.m.wikipedia.org/wiki/Hallands%C3%A5s_Tunnel https://en.m.wikipedia.org/wiki/Hallands%C3%A5s_Tunnel