Development trend of rail-mounted container gantry cranes （STS/RMG/RTG）

In order to improve the efficiency of yard operations, rail-mounted container gantry cranes tend to be larger and more automated, and container bridge cranes that travel at high speed on elevated structural rails composed of reinforced concrete columns and rail beams are being developed.

（1）Rail-mounted container gantry cranes Rail-mounted container gantry cranes have begun to be put into operation in major container hub ports around the world. Except for the need to add rails in the container yard, they are superior to tire-mounted container gantry cranes in terms of stack height, stack positioning accuracy control, anti-roll performance and steel structure stress state. Because they are rail-mounted, they can withstand greater loads by increasing the number of wheels. Therefore, the span of rail-mounted container gantry cranes is increased. Because they are powered by power cables, the power output is stable; using electronic anti-roll systems, some large foreign professional companies are developing fully automatic unmanned container anti-roll positioning systems with positioning feedback devices to improve operating efficiency.

（2） Container bridge cranes Container bridge cranes have been developed and used abroad in recent years. Its basic form is similar to that of a bridge crane, with the lifting height and the height of the concrete elevated corridor determined by the container yard and stack height.

Container bridge cranes utilize an off-track box-beam structure. To facilitate the placement of electrical equipment, one of the beams has a larger cross-section, requiring a walkway in addition to housing the electrical cabinets. The trolley is essentially the same as other trolleys. The trolley's operating mechanism is characterized by its high operating speed, significantly improving container loading and unloading efficiency.

Container bridge cranes utilize a fully automatic electronic stabilization and positioning control system. Due to the trolley's high operating speed, special considerations are taken to mitigate sway in both directions of travel. Power is supplied by both busbars and cable reels.