Great Western Main Line

The Great Western Main Line (GWML) is a railway line running from London Paddington to Bristol Temple Meads via Bath Spa. The GWML is operated by Great Western Railway with CrossCountry and Elizabeth line also operating services along parts of the route. The GWML is fully signalled by Network Rail's Thames Valley Signalling Centre in Didcot. The route is electrified as far as Chippenham from London Paddington with diesel traction being required for the last part into Bristol Temple Meads.

Heritage Railways

The GWML features several Heritage Railway which have connections to it.

Southall West Coast Railway is located next to Southall Elizabeth Line station.

Cholsey & Wallingford Railway is meets the GWML at Cholsey station which receives a half hourly Monday to Saturday, London Paddington to Didcot Parkway services operated by Great Western Railway with the Class 387 Electrostar.

Didcot Railway Centre is located in the triangle by Didcot Parkway station between the Oxford avoiding lines and GWML. The Didcot Railway Centre is owned by the Great Western Society. The Didcot Railway Centre housed the Great Western Railway Class 800 IET fleet during the Christmas Engineering works in 2024 to enable units which would have been trapped at North Pole Depot by future Old Oak Common station to be useable on services.

STEAM Swindon is a museum which is located in the former Great Western Railway workshops in Swindon.