Rail-mounted gantry crane(RMG) is a specail handle equipment in the container yard. It can travel on rail driven by the yard power, and lift and stack containers in the yard area with the equipment of the 20’ or 40’ telescopic spreader (or twin-lift spreader if needed). Compared with the rubber-tyred gantry crane(RTG), the RMG has the advantages of being driven by electrical power, clean, bigger lifting capacity, and high gantry traveling speed with cargo.