Central line (London Underground) and Great Eastern Railway buildings east of , from when the line to Epping was a rural branch line. In terms of total passengers, the Central line is the busiest on the Underground. In 2011/12 over 260 million passenger journeys were recorded on the line. It currently operates the second-most frequent service on the network, with 34 trains per hour (tph) operating for half-an-hour in the westbound direction during the morning peak, and between 27 and 30 tph during the rest of the peak. This makes the Central line the busiest and most intensively-used railway line in the United Kingdom:
London Underground well as many of London's bus and tram operators. Only the Metropolitan Railway, along with its subsidiaries the Great Northern & City Railway and the East London Railway, and the Waterloo & City Railway, by then owned by the main line London and South Western Railway, remained outside the Underground Group's control. A joint marketing agreement between most of the companies in the early years of the 20th century included maps, joint publicity, through ticketing and UD signs, incorporating the first bullseye symbol, outside stations in Central London. At time, the term Underground was selected from three other proposed names;