Ashendon Junction

Ashendon Junction in Buckinghamshire, England, was a major mainline railway junction where, from July 1910, the Great Western Railway's (GWR) London-Birmingham direct route diverged from the Great Central Railway's (GCR) main London-Sheffield route.^[1] It was near the small village of Ashendon, about 10 miles north-east of Oxford.

The junction was where what is now the Chiltern Main Line (formerly the "Birmingham Direct Line" aka "Bicester cut-off" of the GWR), inaugurated in 1910, joined the post-1906 "Alternative Route" alignment of the GCR. It was located 3 miles 44 chains (5.71 km) north-west of today's Haddenham and Thame Parkway; 44 miles 4 chains (70.89 km) from London Paddington via Northolt Junction, and 45 miles 31 chains (73.04 km) from London Marylebone via Neasden and Northolt Junctions.^[2] It was a high-speed flying junction carrying southbound GWR trains from Birmingham via Bicester North (Engineer's Line Reference NAJ2) on an embankment with a girder bridge over the top of northbound Great Central trains travelling from London Marylebone on to the 90 mph five-mile link to Grendon Underwood Junction (Engineer's Line Reference GUA) where they rejoined the original Great Central Main Line towards Brackley and beyond to the East Midlands and North.^[1] The signal box, located on the up side of GCR tracks was the only one on the joint line of a GCR design. Signalling was also of the GCR upper quadrant type.