St Marys railway station is a heritage-listed former goods yard, railway signal box and now railway station located on the Main Western line in the western Sydney suburb of St Marys in the City of Penrith local government area of New South Wales, Australia. The station is served by Sydney Trains T1 Western line services. The station marks the end of the four-track section of the Main Western line. It was designed by New South Wales Government Railways and was built in 1862. It is also known as St. Marys Railway Station Group and St Marys Railway Station. The property was added to the New South Wales State Heritage Register on 2 April 1999.

The Main Western Railway is a major railway in New South Wales, Australia. It runs through the Blue Mountains, and Central West regions. It is 825 kilometres (513 mi) long, of which 484 kilometres (301 mi) is currently operational.