South Acton. Six trains per hour left Hammersmith for South Harrow, three continuing to Uxbridge. In 1925 the inner circle service was ten trains per hour in each direction, but this frequency of service caused problems. A reduction to eight would leave the Kensington High Street to Edgware Road section with too few trains. However the Metropolitan had recently rebuilt it with four platforms as part of an abandoned plan for a tube to Kilburn. The District extended its Putney to High Street service to Edgware Road and the Metropolitan provided all inner circle trains at a frequency of eight trains per hour. In 1923 the London, Midland and Scottish Railway had inherited the line to Barking, and in 1929 proposed quadrupling the line to Upminster and electrifying one pair of tracks for use by the District. On 12 September 1932 services started with new stations at Upney and Heathway (now Dagenham Heathway) with platforms only on the District tracks. Piccadilly line extension In November 1912 a bill was published that included a plan to extend the Piccadilly tube tracks westwards from Hammersmith to connect to the L&SWR's Richmond branch tracks. The bill passed as the London Electric Railway Act, 1913 on 15 August 1913, although the advent of World War I prevented work on the extension. Powers were renewed in 1926 for the quadruple track from Hammersmith to be extended to west of Acton Town, with the concept of the Piccadilly running non-stop on the inner pair. The proposed service split, with the Piccadilly running through to Harrow and Hounslow, was clarified by 1929. District services would run mainly through to Wimbledon, Richmond, Hounslow and Ealing, with shuttles from South Harrow to Uxbridge and Acton Town to South Acton. With finance guaranteed by the Development (Loan Guarantees and Grants) Act of 1929, construction started in 1930. Two additional tracks were built from west of Turnham Green to Northfields on the Hounslow branch. East of Turnham Green a freight loop was built for eastbound coal trains from Richmond to Kensington. Acton Town was rebuilt with five platforms, and a depot was built west of Northfields station. Several stations were rebuilt in a Modernist style influenced or designed by Charles Holden, who was inspired by examples of Modernist architecture in mainland Europe. This influence can be seen in the bold vertical and horizontal forms, which were combined with the use of