Ringbanen

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.

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).

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.

While the freight bypass was being built, plans to move some of the local trains around Copenhagen to electric operations were being laid.

A third connecting curve at Flintholm was built to allow direct running from Vanløse towards Hellerup, and the first S-train service began in 1934 with the route: In 1936 Fuglebakken station between Godthåbsvej and Nørrebro opened, and around 1940 Vanløse station was rebuilt completely as part of the electrification of the Frederikssund line, but this did not significantly affect operations on the Frederiksberg line.

At the same time policial determination to use revenue from Ørestad land sales to finance the Copenhagen Metro was building.

The entire line from Vanløse to Hellerup was closed for a complete track rebuilding for most of 2001 and reopened in early 2002, though only from a temporary terminus north of Flintholm, where all of the connecting curves had been removed.

In 2004 the new large interchange station at Flintholm opened, and from early 2005 the ring line trains could run almost all the way to Ny Ellebjerg.