norwegian kilometer long double track railway tunnel norway running kilometer long section taken use august tunnel constructed drilling blasting method tunnel double track electrified allow maximum speeds kilometres hour mph section stations estimated cost billion norwegian nok tunnel accelerate regional traffic west oslo free capacity oslo commuter rail specifications kilometers long kilometer long section end tunnel mouths meter long arms allowing trains connect correct direction traffic excavated cross section square meters end tunnel end piece consists meter long line branches sides tunnel emergency exits addition additional exits allow emergency exit meters located consists spiral staircase meters deep primarily intended allow access emergency personnel escape route passengers staircase ends smoke tight room line double track electrified allow maximum speeds kilometres hour mph history runs municipalities line built increase traffic west corridor railway west oslo line 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 meter long meter long main contracts building line issued public involved tunnel awarded bid failed win contracts work noisy work avoided work outside tunnels saturdays tunnel built drilling blasting method involved blasting sections meters rock time progress meters week team blasting started june construction meter long section meter long section meters long section system water established allowing water recycled resulted cubic meters expansion port transported away tunnel hour breakthrough took place june october ground failure storage area caused land slip pressed nearby station line oslo metro meters long section platform track pressed meters resulting track lying changes european_union regulations planning project extra emergency installed late final breakthrough tunnel occurred july took place level avoid similar problems occurred construction massive leaks took year fix test area measure level indications change immediately automatically communicated site able act accordingly system automatically pumped water affected areas compensate leaks fixed tunnel water frost tight walls covered highly covered layer installed fire water pipes ventilation systems remove smoke sound tunnel avoid vibrations spreading nearby housing entire tunnel covered layer rock wool december ballast laid january laying tracks ties started work build tracks overhead wires contracted contract electro technical installations awarded nok million section estimated cost nok billion freight trains started tunnel august passenger trains august official opening took place september projects west oslo including new upgrade completion line allow higher service frequency higher faster trains west oslo new high frequency schedule named route plan planned introduction early following delivery new trains allow trains stop stations introduce hourly trains hourly trains stopping main stations west oslo
Bærum Tunnel