The municipalities of Quickborn and Kaltenkirchen and the then independent town of Altona supported this project.

[1] The shares were subscribed by the town of Altona, the communities of Quickborn, Ulzburg and Kaltenkirchen and the construction company Kintzel & Lauser.

However, other colours are used to route plans that show only the AKN lines: red for the A1, green for the A2 and dark blue for the A3.

Since 15 December 2002, the Nordbahn Eisenbahngesellschaft, a subsidiary of AKN Eisenbahn and the Hamburger Hochbahn has operated services from Neumünster to Bad Segeberg on the reactivated Neumünster–Bad Oldesloe railway (HVV line R 82).

Since 12 December 2004, services are extended on line A1 twice a day (Monday to Friday) between Eidelstedt and Hamburg Hauptbahnhof, using its VTA railcars over the S-Bahn tracks and power supply collected from a side-contact third rail.

Since December 2005, additional services of the A2 in the morning and afternoon are extended from Henstedt-Ulzburg to Kaltenkirchen.

The construction of a connecting line to the airport is not supported by the Schleswig-Holstein state government because of the considerable cost burden of at least €150 million.

[6] In preparation for a possible extension of the S-Bahn network, the section from Halstenbeker Straße to the border near Burgwedel station was duplicated up to 2013 and a new Schnelsen Süd station is planned after the Bönningstedt–Quickborn section has been fully duplicated.

AKN has called in the past for the establishment of an all-day grade-separated connection from Eidelstedt to Hamburg Hauptbahnhof, but this failed because it would lead to increased operating costs and because of the limited capacity of the line.