The Hounslow Loop line is a railway line in southwest London which was opened by the London and South Western Railway in 1850. It leaves the Waterloo–Reading line at Barnes Junction and after some seven and a half miles rejoins it at a triangular junction between Whitton and Feltham. Barnes Railway Bridge carries the line over the River Thames. Passenger services, all operated by South Western Railway, either loop back to Waterloo by the junctions or continue southwest via Feltham. The line is electrified at 750 V DC. It provides access to the North London Line for freight services both passing through Clapham Junction to the north east and connecting to the rail network to the south west.

The Waterloo–Reading line is a National Rail electric railway line between London Waterloo and Reading. The line runs west through a series of South West London suburbs to Reading, in central Berkshire. Its passenger operation is by South Western Railway (SWR), which also manage its stations.