Today the partially single-track, fully electrified line features the high-speed Intercity-Express (ICE) service, with its tilting train technology, traveling from Stuttgart to Zürich.

From the city it heads in a southwesterly direction, and runs alongside the nature park Schönbuch between Böblingen und Herrenberg.

Württemberg completed the section from Eutingen to connect to the Upper Neckar Railway (Obere Neckarbahn) in Horb on 1 June 1874.

However, the Royal Württemberg State Railways initially did not attempt to build a much shorter direct connection from Stuttgart to Horb because the gradients seemed too difficult to overcome.

In November of the same year, construction on the technically challenging railway began in Stuttgart, led by the Württemberg engineer Georg Morlok.

On 20 August 1879, after a trial run from Stuttgart to Freudenstadt, the Royal Württemberg State Railways officially opened this section on 2 September 1879, in the presence of Georg Morlok, the president of Württemberg Hermann von Mittnacht, the mayor of Stuttgart Gottlob Friedrich von Hack, and many other dignitaries.

The construction of this section shortened the distance between Stuttgart via Horb and Tuttlingen to Immendingen by 35 kilometers, and cut the trip time by 1 to 2 hours.

Possibly the most famous passenger on this line, Vladimir Lenin, the leader of the Russian Revolution, travelled from Zürich via Stuttgart to Petrograd in a special train on 9 April 1917.

The goal was to enable rail traffic from Berlin to Switzerland and Italy to utilise not just the railways in the neighbouring territories of Baden and Bavaria, but also the tracks owned by Württemberg.

The occupation of the city of Offenburg by French troops in 1923 reinforced the desire for an effective and efficient alternative route.

Travel time between Stuttgart and Singen was cut to 2 hours and 41 minutes in 1933, and the regional and local service schedules also saw marked improvements.

As was true prior to the railway expansion, and since World War I, the Württemberg class C steam locomotives were used in express service.

Starting in 1924, the Reichsbahn began to assign the Prussian G 10 to short-distance freight service, and between 1936 and 1938, the DRG Class 86 saw use in the same capacity.

Axis partner Italy received coal shipments from Upper Silesia using freight trains on the line.

More significant was the damage caused by German troops in April 1945, when several bridges were blown up between Stuttgart and Böblingen, stopping train traffic altogether shortly before the end of the war.

France insisted on its right to reparations, unlike the United States of America, and in 1946 dismantled the second track between Horb and Tuttlingen, which had only been laid a few years before.

On 5 December 1992, the Deutsche Bundesbahn extended the S1 line of the Stuttgart S-Bahn from Böblingen to Herrenberg, thus significantly improving local transport between the Korngäu region and the state capital.

For this purpose, Hulb station was put into operation on 8 December 1990 in Böblingen, opening up the extensive industrial area there.

On the other hand, traffic to the north was largely eliminated; for example, just a single express trains traveled on to Nuremberg at the time.

In 1999, the DB AG radically altered long-distance traffic on the Gäubahn, and stopped, with one exception, using locomotive-powered trains altogether.

One year later, in December 2006, the Cisalpino service was stopped, eliminating direct connections to Italy, and making the ICE the only long-distance carrier on the Gäubahn.

After problems with vehicle availability and delays, ICE operations on the Stuttgart–Zürich route were discontinued on 21 March 2010 and replaced by intercity trains with Swiss Federal Railways carriages.

The Swiss Federal Railways had previously opposed attempts by Deutsche Bahn to use rolling stock from former Interregio services on the international line.

[8] In spring 2012, at a European timetable conference, Deutsche Bahn spoke out in favour of ending long-distance traffic between Stuttgart and Zürich, but failed again due to resistance from the Swiss Federal Railways.

Since the changeover of the two-houlyr RE to IC2, Ergenzingen and Eutingen im Gäu have only been served every two hours from the direction of Stuttgart without having to change trains.

The S 1 service runs from Herrenberg to Stuttgart-Österfeld, where the train leaves the Stuttgart–Horb and travels underground via the Verbindungsbahn to Stuttgart Hauptbahnhof.

From there, the S 1 service utilises the Fils Valley Railway as far as Plochingen, before branching off to Kirchheim unter Teck the terminus of the S 1 route.

In addition, during the work week, a train owned by the Albtal-Verkehrs-Gesellschaft travels between Freudenstadt, Eutingen, and Herrenberg, where it connects to the S-Bahn.

Railion trains travel primarily from the large shunting station near Kornwestheim to St. Margrethen in Switzerland, and go around Stuttgart Hbf.

[13] According to the rail lobby group Pro Bahn, this new line would have extended the distance to Böblingen by 4.4 kilometres and have lengthened the trip for a Regional-Express train by five minutes.