The invention provides a novel urban rail traffic system, which at least comprises a rail traffic sub system, wherein the rail traffic sub system comprises a locomotive, rail auxiliary support structures, upper traffic rails, lower traffic rails, a power transmission line, a power transmission line hanging arm and rail main support posts, wherein two rows of rail main support posts are buried in the direction along the rail line; the lower traffic rail are respectively erected at the top end of each row of rail main support posts; the rail auxiliary support structures are of a frame-shaped structure and are erected on the rail main support posts at intervals in the direction along the rail line; the upper traffic rails are connected with rail auxiliary support structure upper frameworks, are downwards arranged, and are positioned right above the lower traffic rails; the power transmission line is hung on the rail auxiliary support structure upper framework through the power transmission line hanging arm, and is arranged in a direction along the rail line; the locomotive comprises a compartment, support power combination wheels, a pantograph, a driving motor and support driven combination wheels; the support power combination wheels are arranged at the bottom of the compartment; the top of the compartment is provided with the support driven combination wheels. The system can effectively reduce the operation and maintenance cost.