Tyholttunnelen is a 2.7 kilometres (1.7 mi) long, single track railway tunnel in Trondheim, Norway on Stavnebanen. The tunnel was built by the German forces during World War II as a means to bypass Trondheim in case of a sabotage of the main line. This was a major concern since Trondheim Central Station was built on an artificial island and there are bridges both to the east and west of the station. The tunnel is not electrified and is currently not used for passenger service. The western opening is close to the Gløshaugen campus of The Norwegian University of Science and Technology.