|} The Zürich–Olten line is a major railway line in Switzerland connecting the cities of Zürich and Olten. The original line generally followed the south bank of the Limmat from Zürich to near its confluence with the Aar near Brugg and then it generally followed the south bank of the Aar to Olten. The central section between Killwangen-Spreitenbach and Rupperswil now follows a more southerly route through the Heitersberg Tunnel. The line is electrified at 15 kV 16.7 Hz and much of it has four tracks.