Copenhagen–Ringsted Line

The Copenhagen–Ringsted line is a high-speed railway on Zealand, Denmark, connecting Copenhagen via Køge with Ringsted. The line was inaugurated on 31 May 2019, and started operating on 1 June as the first high-speed railway in Denmark. It supports speeds of up to 250 km/h (155 mph) for passenger trains as well as a maximum of 24 trains per hour along its length. As of 2023, the speed limit is 200 km/h.

The construction of the Copenhagen–Ringsted Line was largely as a consequence of the conventional Copenhagen–Fredericia/Taulov Line between the Danish cities of Copenhagen and Ringsted having become highly congested. During 1999, the first proposals for the route, prepared by the national Rail Planning Committee, were rejected by the Danish Parliament, leading to further studying and refinement. In 2009, the government formally discounted the idea of simply building an extra track alongside the traditional line and, during the following year, opted to authorise the building of a higher-speed line along a new alignment. National railway infrastructure agency Banedanmark intentionally divided the project's work into individual packages, worth between €30 million and €200 million, which were competitively bid for by multiple consortiums and individual companies.

On 12 September 2012, the construction phase of the programme officially began. In addition to the line itself, other engineering works are also being performed, including the building of two new stations, one at Ny Ellebjerg and the other at Køge North which has now been completed, while additional infrastructure is also being installed at existing stations. By late 2017, reports emerged of severe difficulties having been encountered with the new line's signalling system; according to project officials, initial operations are to be limited to only one train per hour for the first year while remedial work is performed.