Frederikssundbanen

Frederikssundbanen is one of six radial S-train lines in Copenhagen; it connects the city center with a number of Northwestern suburbs (notably Herlev and Ballerup) and other townships until Frederikssund on the Western coast of the Nordsjælland peninsula.

The service pattern on the inner part of the line is the C service which stops at all stations until Ballerup. On the outer part the basic service is H, which runs partially non-stop until Ballerup. The H service is peculiar in that its frequency is not doubled during daylight hours, as all other basic S-train services are. Instead, in the period where C is doubled, half of its trains continue to Frederikssund, providing 6 trains per hour in total on the outer part of the line, too. This daylight-only extension is indicated as "(C)" in the above table.

Kildedal station is the only officially existing station on the S-train network that is not served for the entire service period, as the only trains that stop there are the daylight C extension. After about 19.00 and on Sundays no trains stop at Kildedal.

The Frederikssund line opened in 1879 as a single-track railway to Frederikssund from Frederiksberg, which at that time was a station on the main line between Copenhagen and Roskilde. In 1911 the main line was moved to connect to the new (current) central station, and the Frederikssund line inside Vanløse was replaced with a connecting line to Valby. The old line between Frederiksberg and Vanløse had a quiet existence until April 3, 1934, when it became part of the first S-train line. Much later this piece of railway metamorphosed again and became part of the Copenhagen metro.

Later in 1934 S-train service was extended westwards from København H until Valby, and in 1941 the section Valby-Vanløse was upgraded to double track and S-train service too. Passengers to stations farther out would ride the S-train to Vanløse and change to steam trains (later diesel) there. In 1949 S-train service was extended to Ballerup, and at the same time the line was double-tracked as far as Herlev. A second track between Herlev and Ballerup was built 1966-1970.

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