 Meanwhile , to the north of Aylesbury the Buckinghamshire Railway was being built by Sir Harry Verney . The scheme consisted of a line running roughly southwest to northeast from Oxford to Bletchley and a line running southeast from Brackley via Buckingham , joining roughly halfway along the Oxford – Bletchley line . The first section opened on 1 May 1850 , and the rest opened on 20 May 1851 . The Buckinghamshire Railway intended to extend the line southwards to connect to its station at Aylesbury , but this extension was not built . 
