Also known as the Quainton Tramway, Wotton Tramway, Oxford & Aylesbury Tramroad and Metropolitan Railway Brill Branch.
Privately built in 1871, becoming in due course part of the Metropolitan Line in 1933, but was closed in 1935.
The Wikipedia page is  and has extensive coverage of the topic. There is also [https://en.wikipedia.org/wiki/Infrastructure_of_the_Brill_Tramway Infrastructure of the Brill Tramway]
Film of the last journey on the Tramway here