 On the outbreak of the First World War in 1914, Brill became a centre for training cadets, who were housed in Wotton House and ferried in trains of five passenger coaches.The Metropolitan Railway was unhappy with the performance and safety of the D Class locomotives and sold them between 1916 and 1922.With much of their route close to London now electrified the MR had surplus steam locomotives, and two Metropolitan Railway A Class locomotives, numbers 23 (built 1866) and 41 (built 1869), were transferred to the route.