 The 1906 motor cars were withdrawn, and the trains were completed by the addition of Standard Stock motor cars, built by the Metropolitan Carriage & Wagon Company in 1927.At the time, the Piccadilly line was being extended, with the extensions involving open-air running, and the 1920 stock was unsuitable for use in wet conditions.It was therefore transferred to the Bakerloo line between January and October 1932.