norwegian meter long railway tunnel norway line tunnel runs built stage line construction started february tunnel opened august tunnel built drilling blasting method construction blasting accident tunnel opened problems leaks damaging infrastructure tunnel double track electrified allows maximum speed kilometers hour mph cost build tunnel excluding infrastructure million norwegian nok tunnel accelerated regional traffic west oslo freed capacity oslo commuter rail old line specifications meter long tunnel cross section varying square meters carries double tracked line tunnel runs slate limestone local occurrences rock line electrified allows maximum speeds kilometers hour mph tunnel frost isolation meters tunnel end frost fans ensure air stays middle tunnel hinder cold air reaching past frost isolation history runs municipalities line built increase traffic west corridor traditionally railway west oslo limited capacity mix local regional freight trains caused delays poor tracks trains stops allows regional trains pass local stations east running local trains freight trains faster trains run new track line built stages built second stage tunnels line kilometer long kilometer long work geological surveys area started prior surveys performed norway contract build tunnel section awarded costing nok million tunnel built drilling blasting method points entry entrance work started february concluded construction involved blasting cubic meters drilling kilometers holes pre injection construction cubic meters cubic meters concrete bolts cubic meters frost protection cubic meters frost isolation kilometers cable near entrance tunnel closest surface meters residential houses construction construction slow meters week half time choke tunnel construction accident worker driving wheeled meters blasting disabled receive compensation working contractor sole proprietor wage criticized improper safety routines required improve concluded criminal offenses committed concern people living tunnel subject low frequency noise originally municipalities demanded residents subject maximum appealed requirements permitted allow march test tunnel requirements met low frequency sound difficult predict measurements opening tunnel showed background noise subject higher nearly impossible measure passing trains major concerns leaks construction year delay severe cost improper construction methods main aims project avoid similar leaks criteria set imp gal gal minute meters achieved sufficient time pre injection continuous entire tunnel water tunnel caused types damage places track causing places fell electrical equipment issues water running walls collecting cable limestone water mixing ballast emergency lighting system replaced high humidity stated savings specifications water frost protection methods caused high maintenance costs small leaks present lot harm addition areas leaks suffer trend older tunnels nearly maintenance free newer tunnels incurred high maintenance costs laying tracks signaling power supply infrastructure cost entire section nok million work february march opening tunnel rest section took place august
Skaugum Tunnel