The €510m project will involve rebuilding a 13km section of the Troisdorf – Koblenz line with construction of a third or fourth track, new stations, and 15.5km of noise barriers. The extension will have six stations, including a new interchange with Bonn light rail Line 66 at Bonn Vilich.

Services will operate at intervals of 20 minutes or less and the extension will significantly improve links between the city of Bonn and Cologne-Bonn Airport, which is already served by Line S13 trains.

In addition to a more frequent passenger service, the widening of the line from two to three or four tracks will provide additional capacity for freight trains on this busy section of the Rotterdam – Genoa corridor, largely segregating regional passenger and freight traffic.

The project also include the construction of a 15-track stabling yard at Cologne Nippes.

The federal government and infrastructure manager DB Networks will fund €461.7m of the project cost through the Performance and Financing Agreement 2 (LuFV2) for 2015-19, with the remaining €47.5m coming from the North Rhine Westphalia government.

Construction is expected to begin in 2017.