The Bærum Tunnel (Norwegian: Bærumstunnelen) is a 5.5-kilometer (3.4 mi) long double track railway tunnel in Bærum, Norway. Running between Marstranderveien and Engervannet, it will make up most of the 6.7-kilometer (4.2 mi) long section of the Asker Line between Lysaker Station and Sandvika Station, which was taken into use on 26 August 2011. The tunnel was constructed from 2007 using the drilling and blasting method with three crosscuts. The tunnel has two tracks, is electrified and allows for maximum speeds of 160 kilometres per hour (99 mph). The whole section between the stations is estimated to cost 2.7 billion Norwegian krone (NOK). The tunnel accelerates intercity and regional traffic west of Oslo and frees up capacity for the Oslo Commuter Rail.