Bærum Tunnel - Specifications

Specifications

The Bærum Tunnel is 5.5 kilometers (3.4 mi) long and is part of the 6.7-kilometer (4.2 mi) long section of the Asker Line between Lysaker and Sandvika. At Engervannet, at the Sandvika end, the tunnel mouths out with two 400-meter (1,300 ft) long arms, one on each side of the Drammen Line, allowing trains to connect to the correct direction of traffic through Sandvika. The excavated cross-section is 110 square meters (1,200 sq ft). At the Lysaker end, the tunnel has an end-piece which consists of a 150-meter (490 ft) long culvert and the Drammen Line branches off on both sides of the tunnel. The three crosscuts, at Blommenholm, Fossveien and Skallum, will be used as emergency exits. In addition, there are three additional exits, to allow for an emergency exit every 1,000 meters (3,300 ft), located at Ballerud, Engerjordet and Njålveien. Each consists of a spiral staircase up to 55 meters (180 ft) deep. These are primarily intended to allow access for emergency personnel, rather than as an escape route for passengers. Each staircase ends in a smoke-tight room. The line will have double track, be electrified at 15 kV 16⅔ Hz AC and allow for maximum speeds of 160 kilometres per hour (99 mph).