大都會線
The identity of the East London line changed considerably during the London Underground era. On Tube maps between 1933 and 1968 it was depicted in the same colour as the Metropolitan line. In 1970, it was renamed the "Metropolitan line — East London Section", in Metropolitan line purple with a white stripe down the middle. In the 1980s it became a line in its own right (though it was still grouped operationally with the Metropolitan line) and from 1990 its colour on the map changed to orange.