It was opened on 18 August 1859 by the Swiss Northeastern Railway (German: Schweizerische Nordostbahn, NOB).

In 1845 a delegation travelled from Zürich to Baden to promote a concession for a railway from Basel to Waldshut.

The treaty specified a maximum gradient of 1.2 percent and the operation three pairs of trains per day.

The line was single track, but the planning and construction provided for eventual duplication.

This ownership is unusual, because the property boundaries of railways usually are immediately next to stations or service depots, but not in the middle of a line.

Immediately after Turgi station the line turns in a sharp curve to the north and cross a three span stone bridge over the Limmat.

Between Siggenthal-Würenlingen and Döttingen stations it includes a roughly five kilometre long, straight section that is not common in Switzerland.

The route has three major engineering structures: The original three intermediate stations at Siggenthal, Döttingen and Koblenz have identical station building, which in turn are identical with the Rupperswil building on the Brugg–Aarau railway, built the same year.

Siggenthal-Würenlingen station was added in 1912 to serve the Siggenthal cement works, now part of Holcim and has a large volume of freight traffic.

Passenger traffic on the line to Stein-Säckingen has been transferred to road between Laufenburg and Koblenz.

Since Switzerland became part of the Schengen Area in 2008, checks on people have disappeared and the declaration of goods for customs is no longer carried out there.

There is also a pair of trains on the Waldshut–Bülach–Winterthur route (line S36 of the Zurich S-Bahn, formerly S41), which reverses in Koblenz.

All services run through Koblenz at the same time, so there is always a narrow period for transferring between trains.