 In 1883, the Duke of Buckingham announced plans to upgrade the route to main line railway standards and extend the line to Oxford, creating a through route from Aylesbury to Oxford. If built, the line would have been the shortest route between Aylesbury and Oxford at the time. Despite the backing of the wealthy Ferdinand de Rothschild, investors were deterred by the costly tunnelling proposed, and the Duke was unable to raise sufficient funds. In 1888 a cheaper scheme was proposed, in which the line would be built to a lower standard and wind around hills to avoid tunnelling. In anticipation of this, the line was named the Oxford & Aylesbury Tramroad. Although the existing line was upgraded in 1894, the extension to Oxford was never built. Instead, the operation of the Brill Tramway was taken over by London's Metropolitan Railway, and Brill became one of their two north-western termini. The line was rebuilt a second time in 1910, and more advanced locomotives were introduced, allowing trains to run faster.
