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evolutionsummer2013

INfrasTrucaTerW The next batch of tube lines included gas production and in concrete causes manager Albert Stanley, later Lord Ashfield) construction of the Waterloo & City severe corrosion of steel reinforcement. promoting expansion of the Northern, Line (opened 1898) the Central London Central, Bakerloo and Piccadilly lines. Railway (Central Line – opened 1902) LU has established where this material The Metropolitan Line concentrated the Baker Street & Waterloo (Bakerloo resides and has introduced measures to on outer suburban services with Line – opened 1906) the Great Northern control loading on slabs and to control the development of ‘metro-land’ including Piccadilly & Brompton (Piccadilly Line interface with moisture/water ingress. new lines to Watford and Stanmore plus – opened 1906) and the Charing Cross development of housing estates. Euston & Hampstead (Northern Line – The stations associated with the opened 1907). These were all constructed Underground Group were distinctive with This period of expansion produced some on a similar basis to that of the City & a common identity designed by architect of the most iconic architecture on the LU South London Railway (C&SLR), ie with Leslie Green. These buildings were of steel network with the Underground Group small diameter running tunnels and lifts at frame construction clad with tiles inside appointing Charles Holden as the architect stations. and out. There are many of these original with his lean designs of brick, concrete buildings and façades remaining with the and framed glass. It was this period that Typically the stations suffer from varying wonderful finishes hiding a mixture of established the elements of what developed degrees of water ingress in particular at the concerns as the structural frames and into the underground house style and later interface between the clay and overlying concrete slabs have succumbed to the the identity of London Transport. In 1933 gravels. One of the biggest maintenance attack of water and time leaving a legacy of the London Passenger Transport Board issues has been managing this water ingress maintenance difficulties for LU to manage. was established bringing together the and the effects that it has on the various underground railways with London’s assets in the stations in particular corrosion, Growth and expansion, buses and trams. ie steelwork, electrical equipment and the 1910 to 1939 ambience of public spaces. The Underground Group plus the other Eighty years later LU has the responsibility railway companies continued to ‘grow’ the to maintain this wonderful architecture This era of tube construction was business and introduced developments but at a cost as the concrete structures greatly influenced by an American similar to American urban railways have deteriorated with the effects of consortium (lead by Charles Tyson Yerkes, including automatic colour light signals the years. This includes the effects of Underground Group) who introduced and escalators, the first of which were carbonation and the difficulties of access techniques and materials from the USA. installed at Earl’s Court station in 1911. to maintain and clean high level glazing and One such material was clinker aggregate There were line extensions, amalgamations structural elements. Obtaining replacement concrete used extensively in station and development of the suburbs with components and sympathetic repair is an buildings. Clinker is a waste product from the Underground Group (under general ongoing problem for its maintainers. After the Second World War some 1930s plans were completed with opening of extensions to the Central line east and west in the 1940s. This brought to an end a great period of expansion and construction. A key development employed in this extension was the use of pre-cast concrete bolted tunnel linings in place of the traditional cast iron. This was a huge success and to this day they perform well with few concerns. 1960s/1970s Post-war austerity and new planning controls (ie green belt) brought expansion to a halt following the opening of extensions to the Central line. However, in 1962 London Transport received authority to proceed with a brand new tube line to cross London north to south. The Victoria line opened in two stages initially from Walthamstow to Victoria (1968) followed by the Brixton extension in 1971. Again this tube line included technical advances with construction of the tunnels using tunnel boring machines and non-bolted ‘flexible’ concrete linings in the London clay. The alignment was unconstrained by overlying development enabling a fast direct line. The railway was, for its time, the most technically advanced underground railway in the world with automatic train operation Figure 4: Passenger waiting area at Gants Hill Station designed by architect Charles Holden. and automatic ticket checking and gated Said to be inspired by the Moscow Metro stations, it has a grand barrel-vaulted ceiling design station entry. 4


evolutionsummer2013
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