Cape Breton's mining industry dictated the need of an outlet in Louisbourg to link the various railways around Sydney with Louisbourg's ice-free harbour, allowing for year-round shipping of coal. The first attempt in 1873 was a narrow, poorly functioning gauge line.
The S&L Railway, one of the most modern lines in Canada, replaced this in 1895. The volume of freight hauled by the S&L rose sharply during its early years. The number of passengers on the S&L, mainly employees of the mines going to and from work, reached a peak of 176,000 in 1913.
By the 1950's the S&L had 31 steam locomotives operating over 116 miles of track, 39 miles of which was main line. The railway employed 400 employees, hauled 4 million tons of freight annually, chiefly coal, more per mile than any other railway in Canada. During both world wars the ports of Sydney and Louisbourg were staging areas for Atlantic convoys and the S&L was a vital link in the supply of fuel and steel. Until regular air service to Newfoundland was offered, both ports were also a terminus for rail and passenger traffic between Newfoundland and the rest of Canada.
S&L ran picnic excursions and blueberry specials that would stop anywhere to let passengers off, and pick them up in the evening. Hunters and vacationers would flag a train and get on, and the crews alway took a lively interest in the latest news along the line. Many times in foul weather and blizzards, the S&L sent out a locomotive and a car to take a doctor somewhere, or bring someone into the hospital.