Since the 11th edition of London's Underground was published in 2010 there have been many important changes on the capital's underground system, not least of which is the significant investment which has gone into the underground network, which is now run by Transport for London which has been implementing its Tube Improvement Plan since 2003 to create extra capacity on the crowded system. Among the many changes to be recorded is the legacy of massive planning and development required by the 2012 London Olympics, the new S Stock that is being introduced on the Circle, District, Hammersmith & City and Metropolitan Lines, the 2009 stock on the Victoria Line, and old stock withdrawn, signalling updated on the District and Victoria Lines and air conditioning introduced on the new sub-surface stock. 2013 also saw a number of events on the network to celebrate 150 years of the London Underground. The new 12th edition brings the work completely up to date with all the changes that have occurred since 2010, and includes a whole new range of illustrations to accompany the text.