The Edinburgh Suburban and Southside Junction Railway was a railway company that built an east-west railway (known as the Edinburgh Suburban Line or more familiarly the Sub) on the southern margin of Edinburgh, Scotland, primarily to facilitate the operation of heavy goods and mineral traffic across the city. The line opened in 1884. Although its route was rural at the time, suburban development quickly caught up and passenger carryings on the line were buoyant; the passenger service operated on a circular basis through Edinburgh Waverley railway station.