The Western Section route is located partly on existing lines and partly on a section of mothballed railway between Bedford and Oxford, Milton Keynes and Aylesbury Vale.

Oxford to Bicester Village has been significantly upgraded by Chiltern Railways and Network Rail as part of the scheme to introduce a new service between Oxford, Bicester and London Marylebone. This project has been delivered as Phase 1 of the overall East West Rail project and includes the additional infrastructure required for East West Rail train services. Chiltern Railways began services from Oxford to London Marylebone via Bicester on 12th December 2016.

Phase 2 of the Western Section covers the route from Bicester Village to Bedford (now due to open in 2023), and Milton Keynes to Aylesbury (due open in 2024).

The line East of Bicester to Claydon Junction that is currently only used by freight trains and will be upgraded for fast passenger services.

The section of rail track between Claydon Junction and Bletchley has been out of use and ‘mothballed’ since the early-1990s and will be rebuilt. A new station will be provided at Winslow.

Train services on the East West Rail line will then follow the existing Marston Vale Line from Bletchley to Bedford. New high-level platforms will be provided at Bletchley, which connects with West Coast Main Line, allowing East West Rail trains to run to Milton Keynes.

The East West Rail project may ultimately include upgrading of the route between Oxford and Bedford to a two-track railway. It is further anticipated that train services will extend to Reading, using existing operational lines.

The Western Section may also provide train services between Milton Keynes and London Marylebone, via Aylesbury. The line between Aylesbury Vale Parkwayand Claydon Junction will be upgraded from use by existing freight services to enable passenger services as part of the East West Rail scheme.