Specifications
The Skaugum Tunnel is a 3,790-meter (12,434 ft) long tunnel with a cross-section varying between 105 and 115 square meters (1,130 and 1,240 sq ft). It carries the double-tracked Asker Line between Asker Station and Solstad. The tunnel runs mostly through Cambrian-Silurian sedimentary slate, nodular limestone and shale, with local occurrences of Permian igneous rock. The line is electrified at 15 kV 16⅔ Hz AC and allows for maximum speeds of 160 kilometers per hour (99 mph). The tunnel has frost isolation 300 meters (980 ft) into the tunnel from each end and frost fans which ensure that the air stays put in the middle of the tunnel to hinder cold air from reaching in past the frost isolation.
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