At Spencer Shops, the Back Shop handled the heaviest railroad work, performing major overhauls and repairs on Southern Railway steam locomotives while the Bob Julian Roundhouse provided routine maintenance. Ceiling-mounted cranes lifted locomotives weighing up to 90 tons and moved them through the building, and a machine shop occupied the eastern side. Completed in 1905, the Back Shop was the largest manufacturing building in North Carolina, built with 2.5 million bricks at a cost of $483,000. Its giant windows and skylights filled the structure with natural light, and the building could hold 15 locomotives at one time within its 596-foot length, 150-foot width, and 80-foot height. Workers produced one completed locomotive per day. After work at Spencer ceased, the shop buildings deteriorated for decades, and by the time they were donated to the State of North Carolina for use as a transportation museum, the Back Shop had hundreds of broken windows, badly damaged brick, and kudzu covering it. Preliminary efforts to prevent further damage, including a new roof, began in 1980, and a more extensive restoration followed more than 20 years later. In 2005, the initial phase of restoration was completed, including another roof replacement after the 1980 roof was damaged by a tornado and by Hurricane Hugo in 1989, foundation stabilization, extensive masonry work, replacement of windows and skylights, and sandblasting and repainting of steel roof trusses. Further restoration remained necessary to complete the building's conversion into an exhibit hall, including a new floor, electrical and plumbing work, interior walls, restroom installation, and more.