West of Nakina, the combined NTR/GTPR line forms CN's transcontinental mainline through to Tête Jaune Cache, British Columbia, and sees very heavy traffic. From Tête Jaune Cache (Yellowhead Pass), the GTPR line to Prince Rupert is a secondary mainline as the CNoR line southwest from Tête Jaune Cache to Vancouver forms the CN mainline. In recent decades, congestion at many ports along the west coast of North America is making the GTPR's development of Prince Rupert an attractive alternative. Canadian National Railways (now a private corporation) recently completed port facilities at Prince Rupert capable of handling two million 20-foot equivalent units (TEU) per year and is lengthening passing sidings on the line from Jasper to Prince Rupert. The CNR now offers daily container train service between Prince Rupert; Chicago, Illinois; and Memphis, Tennessee.