區域線
On 4 July 1932, the Piccadilly line was extended to run west of its original terminus at Hammersmith sharing the route with the District line to Ealing Common. From Ealing Common to South Harrow, the District line was replaced by the Piccadilly line. From South Harrow north, an isolated District line service continued to operate to Uxbridge until 22 October 1933 when the Piccadilly line took over the service to Uxbridge.