The Badminton railway line is a railway line opened in 1903 by the Great Western Railway between the Great Western Main Line at Wootton Bassett in Wiltshire and Patchway and Filton, north of Bristol, England. Forming the eastern section of the South Wales Main Line, it shortened the distance between South Wales and London for heavy mineral traffic and for express passenger trains; it relieved congestion on the line through Bath.

The South Wales Main Line, originally known as the London, Bristol and South Wales Direct Railway or simply as the Bristol and South Wales Direct Railway, is a branch of the Great Western Main Line in Great Britain. It diverges from the core London-Bristol line at Royal Wootton Bassett beyond Swindon, first calling at Bristol Parkway, after which the line continues through the Severn Tunnel into South Wales.