 The DR connected to the Metropolitan Railway (MR, later the Metropolitan line) at South Kensington and, although the two companies were rivals, each company operated its trains over the other's tracks in a joint service known as the Inner Circle. On 1 February 1872, the DR opened a northbound branch from its station at Earl's Court to connect to the West London Extension Joint Railway (WLEJR, now the West London Line) at Addison Road (now Kensington ( Olympia) ). From that date the Outer Circle service began running over the DR's tracks. The service was run by the North London Railway (NLR) from its terminus at Broad Street (now demolished) in the City of London via the North London Line to Willesden Junction, then the West London Line to Addison Road and the DR to Mansion House – at that time the eastern terminus of the DR.
