A further application of such two-system metropolitan railway vehicles is provided in the west of Frankfurt: Starting in Bad Homburg and the Frankfurt Northwest Center so-called Regional Tangent West (RTW) on Eschborn South, Sulzbach (Taunus), Frankfurt-Sossenheim, Frankfurt-Höchst, Frankfurt Airport and Frankfurt Stadium to the Isenburg center in Neu-Isenburg or after Dreieich-Buchschlag run. The Regional Tangent West is to operate as a mixed operation of two-system metropolitan railway car on mostly existing light rail and railway / S-Bahn routes, which makes their realization - despite the great track length - quite reasonably priced. Their primary task is to strengthen the tangential traffic, to spare the passengers tiresome and time-consuming detours via the Frankfurt city center and to reduce the congestion of the Frankfurt City Tunnel. The realization is planned for the end of 2023.