| Rapperswil–Pfäffikon railway | |
| Native Name Lang: | de |
| Linenumber: | 671 |
| Linelength Km: | 3.510[1] |
| Tracks: | mostly 1 |
| Maxincline: | 0.8% |
The Rapperswil–Pfäffikon railway (also known as the Zürichsee-Gotthardbahn, ; ZGB) is a long, mostly single-tracked standard-gauge railway line connecting in the Swiss canton of Schwyz with in the canton of St. Gallen, crossing Lake Zürich using the Hurden peninsula and Seedamm causeway.
The Zürichsee–Gotthardbahn (which is listed in Swiss federal statistics as the Rapperswil–Pfäffikon company) commenced operations over the newly built Seedamm (causeway) from Rapperswil to Pfäffikon on 27 August 1878. The ambitious goal of the joint stock company was the construction of a rail link from Eastern Switzerland to the Gotthard Railway (Gotthardbahn, GB) which was still under construction, and continuing along the shore of Lake Lucerne via Vitznau and Küssnacht to Rotkreuz. In 1879 alone, more than 160,000 Swiss francs were invested in planning a projected extension from Pfäffikon to . The federal government contributed 100,000 francs to the cost of the causeway construction, which included a road (German: Hauptstrasse 8) and a footpath as well as the railway. In addition to the operation and maintenance of the railway, the ZGB was responsible for maintaining the road on the causeway. In order to be able to dispense with further investments in rolling stock and operational facilities, the ZGB transferred operations to the United Swiss Railways (Vereinigte Schweizerbahnen; VSB), which had a large rolling stock depot in Rapperswil. The operations, which always ran at a deficit, stopped at Rapperwil, where the ZGB connected with the Lake Zürich left-bank railway.
Although the company had a concession to build a link to the Gotthard Railway, no significant effort was made to build it. When another initiative committee tried to get a concession for a Pfäffikon–Brunnen or Pfäffikon–Arth-Goldau railway, the ZGB sold it the land surveys that it had already carried out. Finally, on 12 August 1889, the existing initiative committees, the Wädenswil-Einsiedeln-Bahn (Wädenswil-Einsiedeln Railway) and the ZGB signed a merger agreement to found the Südostbahn (Swiss Southeastern Railway; SOB). The SOB started operations on 1 January 1890 and ended VSB operations on the Rapperswil–Pfäffikon line on 5 August 1891. When the SOB acquired the ZGB, nearly 90 percent of the share capital and 25 percent of the fixed bonds were written off. The Südostbahn, to which the Rapperswil–Pfäffikon line now belonged, opened the Pfäffikon–Arth-Goldau railway on 8 August 1891, which gave Rapperswil access to the Gotthard Railway. The SOB started electric operations on 15 May 1939. A section of double-track between Pfäffikon Nord and Pfäffikon has relieved the congested line over the Seedamm since 6 June 2004. SBB S-Bahn services are now operated over the SOB line.
Five trains run every hour in each direction over the Seedamm in 2019:[2]
In the early hours of Saturday and Sunday mornings, the SOB-owned station is served only by line S5 the SBB as part of its night network.[2]