Ringbanen

Ringbanen (the "ring line") is an S-train line in Copenhagen. It runs roughly semicircularly (because a full circle is not possible, Copenhagen being a seaside city) around the central part of Copenhagen and connects the S-train radials about 5 km out.

Trains on the ring line carry service designator F (S-train) and run from 5:30 to 0:50. In the period between about 7.00 and 19.00 on Monday to Friday, there is one stopping train every 5 minutes. Outside this period, there is one stopping train every 10 minutes.

The ring line started as a freight bypass railway. In 1900 Copenhagen had a central station situated just inside Skt Jørgens Sø, from which railways went towards Roskilde (via Frederiksberg) and Hellerup (via Nørrebro, not the current station but where Nørrebroparken is now). A connecting line directly from Nørrebro to Frederiksberg was used by transiting freight, in order to relieve the central station which had been pushing its capacity limit for decades. Apart from capacity problem, the lines through Frederiksberg and Nørrebro had many level crossings, to the increasing irritation of motorists as their number and the number and trains both grew.

These problems were solved for passenger trains by the new (current) central station opened in 1911 and its underground connection to Østerport was finished in 1921 (after delays due to World War I). The new station and its approaches let trains reach the station from north or west without any level crossings at all, and the new station was so voluminous that it did not begin to have capacity trouble until about 1990.

A new large central freight yard south of the current central station had been opened in 1901, but to reach it, freight trains from the north still had to use the old lines Hellerup-Nørrebro-Frederiksberg-Vigerslev to get to the freight yard's approaches. Instead of trying to separate the old line from road traffic it was decided to build an all new grade-separated freight bypass a bit farther out from the city, which is what eventually became today's Ringbane.

The new freight bypass opened in 1930. It diverged from the old Hellerup line at the large shunting yard Lersøen between the present Ryparken and Bispebjerg stations, and at Vigerslev (present-day Danshøj) joined the approaches to the freight yard. At Flintholm there were connecting curves from north and south towards Frederiksberg (which in those days was an important freight destination), and at Vigerslev a double-track triangle junction allowed trains going to the freight yard or directly towards Roskilde.,

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Wikipedia