The
Hindenburgdamm or
Hindenburg Dam is an 11 km-long
causeway joining the
North Frisian island of
Sylt to mainland
Schleswig-Holstein. Its coordinates are . It was opened on 1 June 1927 and is exclusively a
railway corridor. The companies that built the Hindenburgdamm, a job that took four years, were Philipp Holzmann AG of
Frankfurt, working from the mainland, and Peter Fix Söhne of
Duisburg working from Sylt. A train trip along the causeway takes about 10 minutes, and the time between the auto terminals at
Niebüll on the mainland and
Westerland on Sylt is about 30 minutes. The Hindenburgdamm is part of the railway line known as the
Marschbahn ("
Marsh Railway"), which is
double-tracked along much of the route, although there as yet exists a
single-tracked stretch. On the causeway is a
signal box.