There are many types of trailers. Their basic frame, body and traveling system are basically the same as trucks. The railing carriages are usually made of thin steel plates with longitudinal concave prismatic lenses stamped into the railing panels of the carriages, which are transversely welded with convex ribs to increase the stiffness of the brackets and reduce the mass of the brackets. Welding or connecting willow. The longitudinal and transverse beams of the frame are mostly notched interface structure, and the two longitudinal beams are arranged in equal width, which makes the frame have better bending resistance.