The coil car first appeared in the 1960s as a safer way to trans port coiled sheet metal, usually steel, to manufacturers of stamped metal items from car parts to appliances. Prior to that, steel mills had often shipped out coiled metal in open gondolas, exposed to the elements and other sources of potential damage. Coil cars generally have wooden linings to cushion the load, restraints to prevent shifting en route, and a cover for protection. The covers, which can weigh a ton or more by themselves, usually have a central handle for lifting and a pair of brackets to allow the covers to be stacked during unloading or when not in use. Since the covers on many cars are interchangeable, it is not unusual to see cars with mismatched covers.