The THURBO RABe 526 735-6 seen between Buckten and Rümlingen on the Rümlinger-Viadukt

The Basel to Olten Hauensteinstrecke has its most famous construction in Rümlingen. The viaduct was originally built with double track. The line, which was built between 1853 and 1858 connected Basel to the middle of Switzerland and was quite important. Between 1912 and 1916 a new base tunnel of length 8134 m was built making the old main line obsolete. Since then, it only serves the local communities (the Läuferfingli) and has been reduced to single track.