What is the function of the side rail on a trailer?

The function of the side rail on a trailer primarily revolves around enhancing structural integrity and retaining cargo. The side rail contributes to the overall strength of the trailer's frame, helping it withstand the stresses and loads during transport. This structural component not only supports the trailer's overall design but also serves a crucial role in keeping the cargo secure. By having a defined border, the side rail helps prevent shifting or falling of the load, ensuring that cargo remains safely in place throughout transit.

While improving aerodynamics and reducing overall weight are important considerations in trailer design, they are not the primary roles of the side rail. Additionally, while side rails can provide mounting points for accessories, this is more of a secondary benefit rather than their main function. The essential purpose lies in maintaining the integrity of the trailer's structure and securing the cargo effectively.