The Fawley branch line, also known as the Waterside line, is a standard-gauge railway line to Fawley, in the English county of Hampshire. It is on the opposite side of Southampton Water from the city of Southampton itself, in an area known as Waterside. For 40 years a passenger service operated, but this was withdrawn except for the occasional enthusiasts' railtour. The line serves the freight needs of Marchwood Military Port, having also served the same function for Fawley Refinery until 2016.