n with the present day Circle line in London, shown at the bottom of the map. The blue bar marks the northern limit of London Underground operations after 1936, and the black bar the limit of LU operations after 1961.Lobbying from the nearby town of Brill for the introduction of passenger services on the line led to an extension from Wotton to a new terminus at the foot of Brill Hill, north of the hilltop town of Brill itself,[5] in March 1872.[6] Two mixed trains each day ran in each direction.[8][9] With the extension to Brill opened the line was renamed the Brill Tramway.[8] The Duke bought two Aveling and Porter traction engines modified to work as locomotives, each with a top speed of 8 miles per hour (13 km/h),[8][10] although a speed limit of 5 miles per hour (8 km/h) was enforced.[3]The Duke died in 1889. In 1894, the trustees of his estate set up the Oxford & Aylesbury Tramroad Company (O&ATC) with the intention of extending the line from Brill to Oxford, but the extension b