Note:
(a) track gauge
en.wikipedia.org/wiki/Track_gauge
(map: currently: China (same as the two Koreas, UK and US): standard gauge or 1.435m; Thailand (and other mainland Southeast Asia): meter gauge or 1m; Taiwan and Japan: 1.067m)
(b) Needless to say, Taiwan's comes from Japan. For the latter, see 3 ft 6 in gauge railways
en.wikipedia.org/wiki/3_ft_6_in_gauge_railways
(1.067m; 1872 also saw the opening of the first 3 ft 6 in gauge railway in Japan, proposed by the British civil engineer Edmund Morel based on his experience of building railways in New Zealand [in 1862 and 1863])