High-speed rail
First narrow-gauge Japanese high-speed service

In 1957, the engineers at the private Odakyu Electric Railway in Greater Tokyo Area launched the Odakyu 3000 series SE EMU. This EMU set a world record for narrow gauge trains at 145 km/h (90 mph), giving the Odakyu engineers confidence they could safely and reliably build even faster trains at standard gauge. Conventional Japanese railways up until that point had largely been built in the 1,067 mm (3 ft 6 in) Cape gauge, however widening the tracks to standard gauge (1,435 mm (4 ft 8 + 1 ⁄ 2 in)) would make very high-speed rail much simpler due to improved stability of the wider rail gauge, and thus standard gauge was adopted for high-speed service. With the sole exceptions of Russia, Finland, and Uzbekistan all high-speed rail lines in the world are still standard gauge, even in countries where the preferred gauge for legacy lines is different.
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