Electric multiple units have operated on the London Underground since 1898, and exclusively since 1961. They are of two sizes, smaller deep-tube trains and larger sub-surface trains that are of a similar size to those on British main lines.
Electric multiple units have operated on the London Underground since 1898, and exclusively since 1961. They are of two sizes, smaller deep-tube trains and larger sub-surface trains that are of a similar size to those on British main lines. (en)