With the large-scale profile of the new line that had originally been planned, an extraordinarily complex set of lines was considered in the different options. It was estimated that the 18 km long comparison section in Kassel would cost 1.6 to 2.5 billion Deutsche Marks (1975 prices). Planning the location The regional planning process for the Hessian section of the new line was initiated in a letter of 7 February 1974 and later interrupted. It was resumed in a letter dated 21 November 1975, but the district of Kassel—including the urban area of Kassel—was not included initially.<ref name="rpk-1975-11-21">{{cite book |publisher=Kassel region |title=Ausbauprogramm der Deutschen Bundesbahn (DB), Neubaustrecke Hannover–Würzburg (letter, file no. P 6 - 93 c 08 - 05 a') |date= 21 November 1975 | pages= 7 f |language=de}}</ref> In 1977, the city of Kassel pressed strongly for the construction of an underground line through a station under the existing Kassel terminal station–including a tunnel under the city of Kassel. A new station building at the Wilhelmshöhe site and variants with different above ground and underground access lines were investigated. Deutsche Bundesbahn favoured the Wilhelmshöhe location with an above ground approach, the so-called "western route" (Westtrasse). Both options were examined in the regional planning process, which was conducted from 1978 to 1980. Flanked by numerous reports and counter reports they were discussed amid public controversy. The underground option was—in the opinion of Deutsche Bundesbahn—much more complex, more expensive and would impose greater burdens on the population. Discussions at first focused on complex problems of urban development, but gradually shifted to noise abatement issues. On 29 March 1979, Deutsche Bundesbahn opened an exhibition on the construction project in Kassel. The "groundbreaking" ceremony for the Hessian section was held on 13 November 1981. Ultimately, the city of Kassel agreed to the station at Wilhelmshöhe after studies had shown that this site would not adversely affected the future development of the city. High cost and long construction time led to proposals for an underground through station under the main station to be discarded in favour of the peripheral station at Wilhelmshöhe. The new station was initially designed purely as a long-distance station, which would only be used by trains running on the new line. The connection to the existing Kassel Hauptbahnhof would be carried out by shuttle trains. In the course of further planning between 1979 and 1986 it became clear that the