An artifact of the steam era, the BA&P roundhouse curves around a central turntable—a giant lazy Susan used to direct engines into individual stalls. The fire-resistant 1893 structure boasts load-bearing walls four bricks thick. Originally only ten stalls, the railroad doubled the building's size in 1907. The expansion reflected rising freight traffic: engines hauled over 9,000 tons of ore daily in 1910, three times more than in 1894. The engines pulling these loads required up to six hours a day of maintenance. They also needed to be kept under steam (locomotives were rarely started cold.) So each night, hostlers would drive the engines into their stalls, bank their coal fires, and perform routine maintenance. In the morning, they would break the banked fire and otherwise prepare the engine for the day. Electric and later diesel locomotives required much less work than steam engines. In consequence, railroad companies demolished most of the roundhouses that punctuated the tracks. Today, this is one of the few nineteenth-century turntables and roundhouses still in use nationwide.