The Seetal railway line () is a (standard-gauge) railway of the Swiss Federal Railways between Lenzburg and Lucerne in Switzerland. The line was opened in 1883 by the Lake Valley of Switzerland Railway Company, which was owned by British investors, and subsequently owned by the Schweizerische Seethalbahn-Gesellschaft (SthB).
As built, the line had many of the characteristics of an interurban tramway, following the parallel road almost throughout and running within the villages, separating houses from the road. Despite right-of-way improvements and the introduction of narrower trains to avoid clipping accidents, much of this nature has survived to the current day.
History
Inception
thumb|right|Typical roadside track
In the communities of the Seetal valley, it was hoped initially that the main line from Basel to Lucerne would be routed through the valley, but the Swiss Central Railway opted for a route via Zofingen, Sursee and Sempach. At around the same time, the engineer Theodor Lutz developed a concept for the construction of local railways. According to his ideas, these railways should share the use of existing roads, which would anyway lose the most traffic at the newly opened railway. In addition, this allowed the introduction of the local train directly into the town centers.
Lutz managed to raise finance from investors in London to put his ideas into practice on a line through the Seetal. On 22 August 1882 the Lake Valley Railway Company of Switzerland was established in London.
On September 3, 1883, the first section was opened. The passengers included tourists from Lucerne doing sightseeing tours to the Hallwilersee and Baldeggersee lakes. Expansions of the main line followed, as well as a short branch line between Beinwil and Beromünster.
Changes of ownership
thumb|left|Share of the Schweizerische Seethalbahn AG, issued 1. January 1897
The profitable expectations of the British investors were not fulfilled, and so they sold the line in 1894 to the newly founded Schweizerische Seethalbahn Aktiengesellschaft (SthB). They made various improvements, including the introduction of restaurant carriages. They were also pioneers of the electrification of Switzerland's railways, starting electric service in 1910 with 5.5 kV 25 Hz AC. Despite their efforts, the line remained unprofitable.
In 1922 the line was acquired by the Swiss Confederation and incorporated into the Swiss Federal Railways (SBB). In 1930, the SBB modified the electrification to its standard of . Passenger service over the branch line between Beinwil and Beromünster ended in 1992 and the line was abandoned in 2001. It now forms part of a cycle path.
Rebuild
thumb|right|upright|Sign graphically warning of the dangers of the proximity of road and rail on the line
As originally built, the line had 500 unguarded level crossings in a distance of 40 km -- one crossing every 80 m.
Although the line's infrastructure had many of the attributes of a roadside tramway or light railway, it was operated using standard heavy rail rolling stock, with its greater width and longer stopping distances. Various options were investigated, including a major realignment of the line to more conventional heavy rail standards, but this had the twin disadvantages of a very high cost coupled with losing the attractiveness of bringing public transport to the hearts of the villages along the line.