A crane is a kind of lifting mechanism for electric hoist with many sets of crane (or more orbit) sharing one or more special crane lifting trolley. Rail device is the core of a crane, it determines the crane can use.

The rail crane is mainly used for the installation and maintenance of large coal mill. Common rail juki's rail apparatus is lifting trolley (electric hoist) from a movable crane rails on the switch to a fixed linear or circular orbit, to achieve a straight line or arc track below the large coal mill and other equipment installation and maintenance; With the main and deputy car rail crane rail apparatus is lifting the car from a movable crane orbit (main engine) to switch to another mobile cranes, another cross in order to realize the workshop equipment installation and wei hua or implement equipment or item of transportation between the adjacent spans in the workshop. With high precision, long life and high degree of automation and reliable performance.