The over span flat car is mainly a kind of reversible electric transport flat car running across the workshop, which can solve the product transportation across the workshop in the factory. It is a kind of electric rail / trackless in plant transportation vehicle, which can solve the product transportation between span in plant. Also known as trolley, electric flat car. The utility model has the advantages of simple structure, convenient use, easy maintenance, large bearing capacity, less pollution, etc. Due to its simple structure and low cost, it is a common track flat car for workshop span crossing, and the maximum running distance can meet 200m.