The 4 ft 6 in track gauge, also called the Scotch gauge, was adopted by early 19th century railways mainly in the Lanarkshire area of Scotland. It differed from the gauge of 4 ft 8 in that was used on some early lines in England. Early railways chose their own gauge, but later in the century interchange of equipment was facilitated by establishing a uniform rail gauge across railways: the 'standard gauge' of 4 ft 8+1⁄2 in. In the early 1840s standard gauge lines began to be constructed in Scotland, and all the Scotch gauge lines were eventually converted to standard gauge. The building of new Scotch gauge railways was outlawed in Great Britain in 1846 by the Regulating the Gauge of Railways Act 1846. From 1903, tram lines of Tokyo adopted this gauge.

The Tokyo Toden or simply Toden, is the tram network of Tokyo, Japan. Of all its former routes, only one, the Tokyo Sakura Tram, remains in service. The Tokyo Metropolitan Bureau of Transportation operates the Toden. The formal legal name is Tokyo-to Densha. Its nickname, "Toden," distinguished it from the "Kokuden".