Square Type Trolley Axle allows the wheel assembly to move freely vertically and to pivot when making a turns. The Axle has cast iron made front and rear cap which are waterproof. The Axle has heavy mild steel made hubs. The Axle is easy to install and has good strength. The Axle has good robustness and accurate dimension. The Square Type Trolley Axle has size of 100 mm and has 54 and 62 inches track length.