Serving only a string of medium-sized market towns between its extremities, the S&D generated a modest internal traffic, and had daunting operational costs, due to the difficulty of its main line. Its strategic significance was as part of a through route between the Midlands and the South Coast, by connecting with the Midland Railway at Bath. The Midland Railway linked Bath to Bristol and via Gloucester to Birmingham and the north. Heavy summer holiday passenger traffic and healthy through freight business was the result, but the long and difficult main line was always very expensive to run.