Chiltern Railways

Chiltern Railways is a British Train Operating Company that has held the Chiltern franchise, the former GCR London Extension and Great Western joint lines from London Marylebone to Birmingham, Aylesbury, Oxford and Stratford-upon-Avon, since 21 July 1996.

Chiltern was originally part of M40 Trains (a management buy-out of the Network SouthEast Chiltern Lines unit), then bought in 2007 by Deutsche Bahn (Arriva). The franchise has been notable for substantial private investment in route improvements: the redoubling of much of the Marylebone–Birmingham route, the reopening of the Bicester chord (the 'Oxford-London' connection), and the introduction of a fleet of Class 165 and Class 168 'Clubman' DMUs.

The Chiltern franchise expired in 2021 and continues under interim direct award arrangements pending re-tendering.