The Cologne-Frankfurt high-speed rail line (in German: Neubaustrecke Köln-Rhein/Main) is a long railway line in Germany, connecting the cities of Cologne and Frankfurt. Its route follows the Bundesautobahn 3 for the greater part. The line's grades of up to four percent require trains with a high power-to-weight ratio which is currently only met by third-generation InterCityExpress trains. It was constructed between 1995 and 2002 at a total cost of € 6 billion according to Deutsche Bahn.
The former Deutsche Bundesbahn (DB) began planning for a network of high-speed lines for both passenger and freight trains in the 1960s. The 1973 federal transport plan included a high-speed line between Cologne and Groß-Gerau (near Frankfurt), as well as between Hanover and Würzburg and between Mannheim and Stuttgart. This plan envisaged that mixed traffic would require:
These specifications would be difficult to achieve either near the traditional Rhine valley route, which follows an entrenched meander, or along DB's preferred route next to the A3, which has long and steep climbs and descents. The second federal transport plan in 1985 (which was drawn up when the first TGV line had been operating for four years) included a passenger train-only railway, which meant that much steeper grades would be acceptable. The technical standards adopted were:
DB negotiated with the states of North Rhine-Westphalia, Rhineland-Palatinate and Hesse over the route. Each state had objections to the bypassing of the cities on the Rhine, particularly Bonn, Andernach, Koblenz, Mainz and Wiesbaden and four other routes were examined that passed through some of these. No agreement was reached and the Federal Cabinet agreed on 20 December 1989 to a recommendation of the Transport Minister to adopt the A3 route and, among other things, to include a station at Limburg.
DB then consulted with the states and community groups over the details of the route. In North Rhine-Westphalia there was considerable debate over the location of the station to serve the Bonn area and on how to serve the Cologne-Bonn Airport. DB decided that the station would be built at Siegburg and that a separate, double line would connect Cologne and the high-speed line to the south with Cologne-Bonn airport for the S-Bahn and ICE traffic. In Rhineland-Palatinate, DB decided that a station would be built north of Montabaur only 21 km north of Limburg Sud, partly to serve Koblenz via the A48, and to reroute a local railway through it.
In Hesse, DB decided to build the Limburg station south of the town at its current location on cost grounds, even though this prevented a connection to the Lahn valley line, which would have provided a connection to Koblenz and Gießen. Options for connections to Wiesbaden were examined in detail, including routing the line through its eastern outskirts. DB eventually agreed to a double-line spur to Wiesbaden along the A66. Options for connections to Frankfurt Airport, the line to Frankfurt central station and to the Riedbahn (the line to Mannheim). It was decided that routing the line into the existing Frankfurt Airport station (now known as the regional station) with two 400 m-long tracks and a 200 m-long track would not be adequate, even if expanded to four or five tracks. DB decided that a separate station across the A3 from the old station would be required and that the line would go on to connect to the Riedbahn both northbound (towards Frankfurt) and southbound (towards Mannheim). DB dropped a proposal for a connection at Westerburg to the Wiesbaden-Frankfurt railway to allow some trains to avoid the airport station to go directly to Frankfurt central station.
The opening of the whole route, which had originally been planned for 1999, took place after numerous court challenges and geological problems, at the end of July 2002. The last tracks of the route in the Schulwald tunnel were installed on 10 July 2001. In the same month the first trips with diesel locomotives were run to adjust the height of the overhead electric lines on the southern section. On 22 October 2001 for the first time an ICE 3 ran on the line, on a 37 km long section between Frankfurt airport and Idstein.
During construction, traffic on the neighbouring A3 was significantly affected and up to 48 building sites with a reduced maximum speed of 100 km/h were operating simultaneously on the autobahn. Up to 15,000 people were employed on the construction of the railway line. 7.5 million m³ of earth was removed during the tunnel construction and approximately three million m³ concrete were poured. 1,400 miners were hired and 13 people died in accidents in the building of the tunnels.
In Cologne ICE trains follow three paths to reach the high-speed line:
The first two routes allow trains to run via Cologne-Bonn airport loop line, rejoining the main route at Cologne-Porz-Wahn.
The high-speed line’s dedicated track begins in Cologne-Porz and are located between the Sieg line and the line from Gremberg yard and the Cologne south bridge, which, in effect, becomes the Right Rhine line when it separates at Troisdorf. Between Porz and Troisdorf there are six parallel lines and the speed limit on the HSL is 200 km/h. At Troisdorf the HSL runs through a 627 m tunnel under connecting lines that allow passenger trains running on the Sieg line to transfer to the Right Rhine line and freight trains on the freight lines to transfer to the Sieg line (and vice versa for northbound trains).
In Troisdorf the Right Rhine line leaves the high speed line and runs through Bonn-Beuel towards Koblenz. The HSL follows the Siegstrecke to the rebuilt Siegburg/Bonn station and then turns south to run through the Siegauen-Tunnel under the Sieg and then joins the A3, which it follows closely to Frankfurt Airport. Between the Siegauen-Tunnel and the Main Bridge (near Frankfurt) the speed limit is 300 km/h and from there to the airport station trains run at 160 to 220 km/h.
In the Wiesbaden suburb of Breckenheim a double line connects to Wiesbaden, partly next to the A66 and then next to the Ländchesbahn. Trains run into the Wiesbaden terminal station and can then reverse reverse to go to Mainz and Mannheim. The 13.2 kilometers-long Wiesbaden branch has a maximum speed of about 160 km/h.
Work is being carried out to create separate tracks for the high-speed line through the heavily used Cologne rail junction from its provisional connection to the conventional line at Köln Steinstraße, where trains are limited to 130-km/h through the points. The line is being extended to Cologne-Mülheim station through Cologne Messe/Deutz railway station (low level). This work was intended to be part of the original high-speed line project, but was dropped to reduce costs. When completed in 2008 this work will reduce the time between Frankfurt/Main and Duesseldorf by 10 minutes.