Any chance of the project proceeding ended with the political change of 1839 when the liberal forces in the canton of Zürich were ousted by the conservatives.

Negrelli left Zürich in 1840 and worked in Austria at the Emperor Ferdinand Northern Railway as Inspector General.

The political situation in Switzerland at that time was not favourable for the building of railways, but it was dominated by the conflict between the Catholics and Protestants, which culminated in the Sonderbund War of 1847.

He knew that healthy financial growth was only possible through improved transport links with other markets, and for that the railway was the tool of the times.

In addition to the terminuses in Romanshorn and Zürich the plans included the following stations: Amriswil, Riedt, Bürglen, Weinfelden, Märstetten, Felben, Frauenfeld, Islikon, Ruchegg, Winterthur, Rikon (Effretikon), Wallisellen and Oerlikon.

It was agreed to build industrial connections from the line to the copper mill in Kupferhammer near Kemptthal and at Haslimühle in Müllheim-Wigoltingen.

Stations at Oberach, Hüttingen, Oberwinterthur and Baltenswil, which were primarily intended to benefit the local population, were all rejected.

The two parallel tracks between Winterthur and Oberwinterthur, which were built separately by the NOB and SNB, were merged in 1903 to form a double-track line.

[4] As a main line, it was quickly electrified by the SBB with its normal power system of 15 kV AC 16.7 Hz.

The Winterthur depot was built in the resulting triangle, but it now has only minor importance apart from the stationing of a fire and rescue train.

The Baroque Revival station building was built by the Swiss Federal Railways (Schweizerische Bundesbahnen, SBB).

Wiesendangen station came to public notice in 1975 when the SBB had the unique and valuable building in the Swiss chalet style demolished at 5 AM on a Monday.

After Attikon, the Winterthur–Romanshorn line runs over a three kilometre-long embankment while descending 85 metres to the Thur valley.

Frauenfeld station, which serves the capital of the canton of Thurgau, has a large and stately entrance building.

While the goods shed was demolished, the neo-classical military warehouse building was converted into a park-and-ride garage.

Bürglen station received a medium-sized entrance building with a gable that faced the track in 1866.

The Bischofszellerbahn company, which opened the Sulgen–Gossau railway on 1 February between Sulgen and Bischofszell-Stadt, also built a locomotive shed at the station.

Romanshorn station is a terminus at a port and has an extensive track layout and a train depot.

Trains from the line from Winterthur gained access to the yard via a connecting loop; the depot is located in the triangle of tracks thus formed.

For this purpose, the S30 is supplemented during the day from Monday to Friday by the extended S8 (Zürich S-Bahn) service running on a fairly irregular half-hourly pattern.

The Thur valley line has lost some importance for freight transport since the closure of the marshalling yard in Romanshorn.

Nevertheless, freight trains from the Rhine Valley and from Lake Constance are routed to Limmattal marshalling yard, as Buchs marshalling yard serves only as a distributing point, but not as a collecting point for national single-wagon traffic.

At the moment (2015–2017), the Winterthur–Romanshorn railway is being modernised from Winterthur to Weinfelden in order to increase the maximum speed from 125 km/h to 150 km/h.