The Lake Line was built in four sections (see below) between 1869 and 1895. The loop via
Konstanz crosses the
border between Switzerland and Germany twice. The sections of the Lake Line were built by two
railway companies, the
Swiss Northeastern Railway (NOB) and the
Swiss National Railway (SNB). The SNB were taken over by the NOB in 1878, and in 1902 the latter was transferred into the
Swiss Federal Railways (SBB). In 1996, the line was taken over by the
Mittelthurgaubahn following a competition. They introduced half-hourly fixed-interval services and modernised both track and rolling stock. When
Mittelthurgaubahn went bankrupt in 2003 the line went into the possession of SBB's subsidiary
THURBO, which had been intended as a joint venture between the SBB and
Mittelthurgaubahn.
Rorschach–Romanshorn On 15 October 1869, the section from to was opened by the NOB. It connected to the already existing railway between Rorschach and of the
United Swiss Railways (VSB), which opened in 1856. Between Rorschach and Rorschach Hafen, the NOB built its own track next to the VSB track and this section is still
double-tracked today while the rest of the line is
single-tracked (except for stations where trains cross regularly). In 1893, the line was connected to the
Thur Valley Railway so that trains could operate between and Rorschach without reversing direction in Romanshorn. The NOB line competed with the
Rorschach–St. Gallen railway and
St. Gallen–Winterthur railway lines of VSB. Between 1869 and 1976,
train ferries operated from Romanshorn to other ports of
Lake Constance.
Romanshorn–Kreuzlingen Hafen–Konstanz On 1 July 1871, not quite two years after the Rorschach–Romanshorn section started operations, the Romanshorn– line opened by the NOB. It connects to the
High Rhine Railway (between
Basel and Konstanz), which opened in 1863. With the incorporation of Emmishofen into the
municipality of Kreuzlingen in 1928, the former Emmishofen railway station changed its name to , and the former Kreuzlingen railway station became .
Etzwilen–Kreuzlingen–Konstanz The section along the
lower Lake Constance (Untersee) was bult by the SNB, whose goal was to build an independent railway line between Lake Constance and
Lake Geneva (
Lac Leman). The section between and Konstanz/Kreuzlingen Hafen opened on 17 July 1875, on the same day as SNB's
Winterthur–Etzwilen railway and
Etzwilen–Singen railway lines. The SNB went
bankrupt in 1878 and its railway lines were taken over by the NOB.
Schaffhausen–Etzwilen The westernmost section between the city of
Schaffhausen and Etzwilen was built by the NOB in order to connect the village of
Stein am Rhein, located in the eastern part of the
canton of Schaffhausen, with the capital of said
canton. The section between Etzwilen and opened on 1 November 1894. The final section between Feuerthalen and , which features a
steel bridge over the
High Rhine and the
Emmersberg tunnel, opened on 2 April 1895 due to delays in construction of the tunnel. ==Electrification==