On reaching Princes Risborough, new construction started. The station was already a major junction, with the single-track line dividing into three branches: to Chinnor and Watlington (which survives in part as the Chinnor and Princes Risborough Railway); to Thame, Wheatley and Oxford; and to Aylesbury. The joint line was constructed in the 'V' formed by the two latter branches, and ran north west to Ashendon (not yet a junction), where the line curved north to join the GCR's pre-1906 main line at Grendon Underwood Junction in Buckinghamshire.