The capacity of a Compressed Natural Gas (CNG) tank trailer can vary significantly based on its design and intended use. CNG tank trailers are used to transport compressed natural gas, which is a clean and environmentally friendly alternative to traditional fossil fuels.

Typically, the capacity of CNG tank trailers is measured in terms of gas volume, often expressed in standard cubic feet (scf) or cubic meters (m³). These trailers can come in various sizes and configurations, and their capacity can range from a few thousand scf to tens of thousands of scf or even more, depending on their specific design and intended application. The choice of capacity depends on factors such as the transportation requirements, range, and the demand of the CNG infrastructure in a particular area.

It's important to note that CNG tank trailers are subject to safety regulations and standards to ensure the secure transportation of compressed natural gas, and the capacity is determined based on these safety requirements and the needs of the industry.