Originally the plan was to extend the line as an underground line directly from København L to the center of the city, but over the course of the 1960s it became clear that the funding environment would not support metro construction in the foreseeable future. Therefore, in the eventual S-train conversion the innermost few kilometers in the line were abandoned and replaced by a large S-curve that connected it to the existing S-train trunk at Svanemøllen. A new overpass and interchange with the ring line was built at Ryparken. København L was abandoned and the terminus of the diesel trains moved to Svanemøllen in early 1976, and a year and a half later the conversion to S-trains were complete. This was the longest single addition to the S-train network so far.