What do tube trailers primarily carry?

Tube trailers are specifically designed for the transportation of pressurized gases. These trailers consist of several cylindrical tubes or containers that are equipped to safely hold gas at high pressures. They are commonly used to transport gases such as hydrogen, oxygen, and natural gas, among others.

The engineering and construction of tube trailers ensure that the gases remain contained during transport, minimizing the risks associated with leaks or ruptures. The pressurization within the tubes is critical because it allows for the efficient storage and transport of gaseous materials, which generally require more space than liquids or solids if not compressed.

The other options listed, while relevant to hazardous materials transportation, do not accurately describe the primary function of tube trailers. Liquid chemicals typically require different types of tank trailers designed to maintain proper temperature and pressure. Solid waste would be transported in specialized waste containers, and biological materials demand containment that often involves different handling and transportation protocols. Thus, the primary role of tube trailers is indeed to carry pressurized gases.