On the evening of 11 January 2026, a train departed for the last time from the terminus of Frankfurt’s underground line U2 in the Bad Homburg district of Gonzenheim, accompanied by representatives of local politics and the transport operator as part of an official farewell ceremony. Since 1971, this had been the terminus of an important connection in the Frankfurt metropolitan area – since then, passengers have had to change to a bus to continue their journey to the centre of the spa town. This is because today’s underground line evolved from an interurban tramway, Line 25 of the so-called Taunus railways, which for many decades previously ran further into Bad Homburg’s town centre and beyond. However, the heavy, longer and wider metro trains were considered unsuitable for the local road, and there were insufficient funds for an underground extension into the centre.
Over the past 30 years, there have repeatedly been initiatives to extend the line beyond its unfavourably located terminus on the outskirts at Gonzenheim. Various options were discussed, but for a long time funding remained a major obstacle.
Around ten years ago, a proposal to extend the line to the interchange hub at Bad Homburg S-Bahn station gained the approval of the responsible bodies. Under this plan, the existing terminus will be abandoned and the line diverted into a 355-metre-long tunnel shortly before the station. A new underground stop, also called Gonzenheim, will be built within the tunnel. The line will then approach the tracks of the regional and S-Bahn services, emerge from the tunnel and continue parallel to the railway tracks as far as Bad Homburg station. In total, 1.6 kilometres of new track will be constructed. Having selected this option to Bad Homburg railway station, any further extension into the old town centre and beyond is, however, not likely to matrialize in the foreseeable future.
The entire construction project received planning approval in 2016, and in a subsequent referendum the project gained over 70 per cent approval on 28 October 2018. In 2020, the Stadtbahngesellschaft mbH Bad Homburg v. d. Höhe (SBHG) was established, and on 9 December 2025 the time had finally come: the first official groundbreaking ceremony for the extension was celebrated. Since 12 January 2026, the U2 has temporarily terminated two stops before Gonzenheim at Nieder-Eschbach, with a replacement bus service in operation. From early March, the underground line is expected to run one stop further to Ober-Eschbach, once track modifications there provide a facility for trains to turn around. According to the current schedule, the new section of line is planned to enter service in 2029.
