TC Pipelines, LP. The Group's principal activity is to transport natural gas. The Group has a 30% general partner interest in Northern Border Pipeline Company and a 49% general partner interest in Tuscarora Gas Transmission Company. Northern Border Pipeline Company owns a 1,249 mile interstate pipeline system that transports natural gas from the Montana-Saskatchewan border to markets in the midwestern United States. Tuscarora Gas Transmission Company owns a 240-mile interstate pipeline system that transports natural gas from Oregon, where it interconnects with the facilities of PG&E National Energy Group, Gas Transmission, Northwest, to northern Nevada.