#12 served the Alton & Southern Railroad for just 22 years, operating 622,626 miles for the industrial switching/transfer line in Illinois. The locomotive's rare 3-cylinder design saved on fuel. Unfortunately, maintenance and associated costs for the center cylinder outweighed the fuel economies. Only four North American 3-cylinder steam engines exist today. #12 weighs 242,000 pounds and has three 22" x 28" cylinders.