Circle line (London Underground) and the C Stock trains have recently been replaced by new seven-car S Stock trains, in a programme completed in 2015. In 1863 the Metropolitan Railway, the world's first underground railway, opened in London between Paddington and Farringdon, connecting the Great Western Railway's relatively remote terminus at Paddington with Euston and King's Cross stations and the City, London's financial heart. In the same year a select committee report recommended an 'inner circle' of railway lines connecting the London termini that had been built or under construction. In the next year the Metropolitan District Railway (commonly known as the District Railway)
Romford–Upminster line am and 8 pm on Sundays. The journey time from one terminus to the other is approximately nine minutes. During the construction of the railway in 1892, the geologist T. V. Holmes discovered a five-metre layer of boulder clay underlying the gravel and sand in a section just north of St. Andrew's Park. This is now the Hornchurch Cutting Site of Special Scientific Interest, which exhibits the southernmost limit of the Anglian ice sheet 450,000 years ago, the furthest south that any ice sheet reached. Romford–Upminster line The Romford–Upminster line is a railway branch line in Greater London that connects