The invention relates to overhauling equipment for a motor train unit, in particular to a movable type top operating platform for overhauling the motor train unit, which is applied to the overhauling operation of a motor train unit roof. In the operating platform, a traveling trolley suspends a movable guardrail and a movable operating trolley on three H-shaped steel rails of a roof; the running of the movable guardrail and the movable operating trolley is controlled by a control system of the movable type top operating platform; the movable operating trolley is provided with a revolving safety guardrail, an arm column type cantilever crane and an operating turnover plate; the movable guardrail is provided with a protective turnover plate and a revolving connection device; and when the movable operating trolley stops operating, the revolving safety guardrail on the movable operating trolley is laid above the motor train unit roof horizontally, and in order to enhance stability, the revolving connection device and the revolving safety guardrail are locked.