Lake Zurich left-bank railway line
The line at Horgen, showing the proximity of Lake Zurich
Service
Route number	720 (Zurich–Ziegelbrücke) 736 (Ziegelbrücke–Näfels)
Technical
Line length	61.31 kilometres (38.10 mi)
Track gauge	1,435 mm (4 ft 8+1⁄2 in) standard gauge
Electrification	15 kV/16.7 Hz AC Overhead line
Maximum incline	1.7  %
Zurich–Ziegelbrücke–Näfels Legend km elev cross-city line from platforms 31–34 S2 S8 0.34 Zürich HB S24 terminus of S25 408 m to Winterthur S24 to Zürich Altstetten and Baden 1.96 Zürich Aussersihl Zimmerberg Base Tunnel 9478 m (left) / 9419 m (right) 2.93 Zürich Wiedikon 405 m SZU goods line to Giesshübel 3.41 Kollerwiese / Wiedikon-Ulmberg tunnel 848 m 3.93 Zürich Enge 409 m Enge tunnel 903 m 5.81 Zürich Wollishofen 409 m 8.86 Kilchberg 424 m 9.68 Nidelbad planned extension of the base tunnel to Zug 10.64 Rüschlikon 433 m 12.09 Thalwil to Zug S24 14.23 Oberrieden 424 m 16.77 Horgen 408 m 20.73 Au ZH 409 m 23.97 Wädenswil 408 m Wädenswil–Einsiedeln railway 27.46 Richterswil 408 m 28.73 Hafen 29.37 Bäch SZ 411 m 31.71 Freienbach SBB 410 m to Arth-Goldau 33.44 Pfäffikon SZ ↑ S8 412 m to Rapperswil over the Seedamm 37.18 Altendorf 412 m 39.58 Lachen 416 m A 3 Lachen 62 m 43.49 Siebnen-Wangen 433 m 46.57 Schübelbach-Buttikon 418 m 49.94 Reichenburg 420 m 54.23 Bilten 421 m Lower Linth canal bridge 62 m Rapperswil–Ziegelbrücke railway S4 S6 57.14 Ziegelbrücke ↑ S2 S27 425 m to Unterterzen – Sargans S2 S4 to Linthal S6 S25 Source: Swiss railway atlas[1]

The Lake Zurich left bank railway line (German: Linksufrige Zürichseebahn), is a railway line in Switzerland. As its name suggests, it runs down the left, or west, bank of Lake Zurich, connecting Zurich to Ziegelbrücke and Näfels.^[2]

The left-bank railway opened in 1875 and forms part of the Zurich–Chur main line. It is 61.31 kilometres (38.10 mi) long, standard gauge, double track and electrified at 15 kV  16.7 Hz AC supplied by overhead line. Between Zurich and Thalwil, the line originally shared its tracks with the Zurich–Lucerne main line, although many through trains on this stretch now use the Zimmerberg Base Tunnel rather than the lakeside line.^[2]

The line was opened by the Swiss Northeastern Railway in 1875. Prior to this, trains between Zurich and Chur travelled on the Wallisellen to Rapperswil via Uster line. The parallel line on the opposite bank of Lake Zürich did not open until 1894.

Between 1875 and 1925, the line followed a routing through Zurich north of Wollishofen that differed from the current alignment and was largely at street level, with many level crossings. The line passed through a single tunnel, the original Ulmberg rail tunnel, and crossed the Sihl river on a bridge. Between 1925 and 1927, this stretch of line was relocated westwards and to a lower level, largely in the new Ulmberg and Enge tunnels, and the current Wiedikon and Enge stations date from this period. The original Ulmberg rail tunnel is still in use for road traffic, forming the western bore of the Ulmberg road tunnel, but most of the rest of the former route has been obscured by subsequent building.^[3]

• Media related to Linksufrige Zürichseebahn at Wikimedia Commons