On the one hand, the sudden fracture of the cross beam of the freight car may be caused by the overweight goods on the car, and on the other hand, it may be caused by the aging of the cross beam and the decline of the bearing capacity because the car has not been overhauled for too long.

A truck is a commercial vehicle designed and equipped mainly for carrying goods, whether it can tow a trailer or not. Trucks are generally called trucks, also known as trucks, which refer to cars that are mainly used to transport goods, and sometimes refer to cars that can tow other vehicles, belonging to the category of commercial vehicles. Generally, according to the weight of the car, it can be divided into heavy and light. Most trucks use diesel engines as power sources, but some light trucks use gasoline, liquefied petroleum gas or natural gas.