Ted: Cased pipeline crossings are a common feature in the industry. They are used primarily at road and rail crossings. The casing (also referred to as the encasement pipe) is a larger diameter pipe that is designed to take the loading from vehicle or train traffic on the road and absorb/deflect that loading from the carrier pipeline inside the casing. In addition to the encasement pipe and the carrier pipe there are other key elements to a case crossing. Notably, there are non-metallic spacers that position the carrier pipe inside the encasement pipe, and dielectric end seals that prevent the ingress of water and soil. Finally, there are vent pipes on each end of the casing. These provide a warning and route product to a safe location in the event of a pipeline leak inside the sealed casing. Pipeline Casing Vents on each side of a road crossing in Chalfont, PA There are tens of thousands of these cased pipeline crossings throughout the United States.