The Rhine Valley rail line is being expanded to four tracks to relieve congestion on the Karlsruhe to Basel line. Local and goods traffic uses the modernized existing section while the new tracks are intended for high-speed long-distance travel. The future tracks of the new ICE section pass under the A5 Autobahn. For safety reasons, the new section must run under the bridge of the A5 Autobahn with a minimum height clearance of 8 m. This means that this new section has to be laid up to 2 m deeper than the tracks of the parallel Rhine Valley line. Because of the high water table in this section, this structure is built as a watertight concrete trough.