Circle line (London Underground) with the other London Underground sub-surface lines: the Hammersmith & City line from Hammersmith to just before Aldgate; the Metropolitan line from Baker Street to Aldgate; and the District line from Tower Hill station to Edgware Road station. The line is electrified with a four-rail DC system: a central conductor rail is energised at and a rail outside the running rail at , giving a potential difference of . The running rails are not electrified. Much of the double track railway from the Hammersmith terminus to Westbourne Park station is on a high brick viaduct. East of Westbourne Park the
Upminster 2010 it formed part of the Upminster constituency. Upminster is within the Havering and Redbridge London Assembly constituency and the London European Parliament constituency. Upminster rises to about above sea level to the north and is about above sea level to the south. It rests on a layer of loam, above sand and gravel in the south and London Clay to the north. It is bounded in the west by the River Ingrebourne and there is a stream running east-west, just north of Corbets Tey that has been dammed to form a lake. It has formed part of the continuously