Metro-land (or Metroland) is a name given to the suburban areas that were built to the north-west of London in the counties of Buckinghamshire, Hertfordshire and Middlesex in the early part of the 20th century that were served by the Metropolitan Railway. The railway company was in the privileged position of being allowed to retain surplus land; from 1919 this was developed for housing by the nominally independent Metropolitan Railway Country Estates Limited (MRCE). The term "Metro-land" was coined by the Met's marketing department in 1915 when the Guide to the Extension Line became the Metro-land guide. It promoted a dream of a modern home in beautiful countryside with a fast railway service to central London until the Met was absorbed into the London Passenger Transport Board in 1933. Metropolitan Railway The Metropolitan Railway was a passenger and goods railway that served London from 1863 to 1933, its mainline heading north from the capital's financial heart in the City to what were to become the Middlesex suburbs. Its first line connected the mainline railway termini at , and King's Cross to the City, and when, on 10 January 1863, this line opened with gas-lit wooden carriages hauled by steam locomotives, it was the world's first underground railway. When, in 1871 plans were presented for an underground railway in Paris, it was called the Métropolitain in imitation of the line in London. The modern word metro is a short form of the French word. The railway was soon extended from both ends and northwards via a branch from Baker Street. It reached Hammersmith in 1864, Richmond in 1877 and completed the Inner Circle in 1884, but the most important route became the line north into the Middlesex countryside, where it stimulated the development of new suburbs. Harrow was reached in 1880, and the line eventually extended as far as in Buckinghamshire, more than from Baker Street and the centre of London. From the end of the 19th century, the railway shared tracks with the Great Central Railway route out of . Electric traction was introduced in 1905 with electric multiple units operating services between Uxbridge, Harrow-on-the-Hill and Baker Street. To remove steam and smoke from the tunnels in central London, the Metropolitan Railway purchased electric locomotives, and these were exchanged for steam locomotives on trains at Harrow from 1908. To improve services, more powerful electric and steam locomotives were purchased in