The Cologne–Frankfurt high-speed rail line () is a railway line in Germany, connecting the cities of Cologne and Frankfurt. Its route follows the Bundesautobahn 3 for the greater part, and currently the travel time is about 62 minutes. 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 Intercity-Express trains. It was constructed between 1995 and 2002 at a total cost of six billion Euro according to Deutsche Bahn. Operational use The line starts in Cologne at the Abzweig Köln-Steinstrasse in the Cologne borough of Porz. Whilst the connection loop to Cologne-Bonn Airport, the Cologne Airport loop, is technically not a part of the high-speed line, it was built as a part of the general refurbishments in the Cologne area due to the line, and hence is generally regarded as part of the project. The line has four stations, Siegburg/Bonn, Montabaur, Limburg Süd and Frankfurt Airport. The line is equipped for speeds up to between Siegburg and Frankfurt, closely following the A3 autobahn. History 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: maximum grade of 1.25% (occasionally 2.0%) curves with small superelevation and minimum radii of maximum line speed of 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: maximum grade : 4.0% minimum radius : maximum speed : 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