Unfolding type steel rail stepping device

The utility model belongs to the technical field of mechanical construction. The unfolding type steel rail stepping device comprises an outer shell, an inner shell, rolling wheels, a support and a driving column, a positioning groove is formed in the bottom of the outer shell, and the positioning groove is correspondingly arranged on a steel rail in a crossing mode; the inner shell is slidably arranged in the positioning groove in a matched mode, a lifting assembly is arranged between the inner shell and the outer shell, and the lifting assembly drives the outer shell to ascend and descend relative to the inner shell; the roller is pivoted on the inner shell, and the roller is supported on a steel rail in a walking manner; the two sides of the bottom of the inner shell are both provided with supports in a pivoted mode, and the supports are in an L shape. Brake assemblies are arranged on the two brackets; driving columns corresponding to the two ends of each support are arranged at the front end and the rear e