The Cumberland Line is a commuter rail line operated by Sydney Trains in Sydney, New South Wales, Australia. It connects Schofields and Leppington stations in the western suburbs. Limited services extend from Schofields to Richmond. The line opened in 1996, following the construction of a 'Y-link' track between Harris Park and Merrylands stations. The intention of this link was to allow direct services to operate from the south west suburbs to Parramatta and Blacktown without requiring a change of trains at Granville. The line takes its name from the Cumberland Plain on which much of Western Sydney was built.

Sydney Trains is the operator and brand name of the train network serving the Greater Sydney metropolitan area in New South Wales, Australia. The network is a hybrid urban-suburban rail system with a central underground core that covers 369 km (229 mi) of route length over 813 km (505 mi) of track, with 170 stations on eight lines.