Paddington became an important milk depot towards the end of the 19th century. A milk dock was built 1881, and by the 20th century over 3,000 churns were being handled at the station every day. Other goods such as meat, fish, horses and flowers were also transported through Paddington. Passenger traffic continued to improve as well. In March 1906, the goods depot at Westbourne Park was moved to Old Oak Common. The main departure platform was extended in 1908 and used for milk and parcels. In 1911, work began to separate light and empty carriage traffic from running trains between Paddington to Old Oak Common, which involved the rebuilding of Westbourne Park station. The work was halted because of World War I but resumed in 1926, to be completed the following year. Three new platforms were added; platform 12 in November 1913, platform 11 in December 1915, and platform 10 the following year. The roof was completely reconstructed between 1922 and 1924, replacing Brunel's original cast-iron columns with steel replicas.