Münden Tunnel a tunnel as well. The tunnel breakthrough was on October 6, 1988. On May 29, 1991 the tunnel was officially opened, along with the Hanover-Fulda part of the high-speed rail line. The cost of construction was about DM 200 million (€102 million). Münden Tunnel The Münden Tunnel () is a railway tunnel on the Hanover-Würzburg high-speed rail line in Germany. It is situated south of the town of Hann. Münden between Göttingen and Kassel. At a total length of 10,525 metres, it is the second longest tunnel in Germany after the Landrücken Tunnel. The tunnel was built between 1983 and
Channel Tunnel techniques from the oil industry were employed. Tunnelling was a major engineering challenge, with the only precedent being the undersea Seikan Tunnel in Japan, which opened in 1988. A serious risk with underwater tunnels is major water inflow due to the pressure from the sea above, under weak ground conditions. The tunnel also had the challenge of time: being privately funded, early financial return was paramount. The objective was to construct two rail tunnels, apart, in length; a service tunnel between the two main ones; pairs of cross-passages linking the rail tunnels to the service one at spacing; piston relief