By 1985, the line was single track for almost its entire length, and it was handling 19 million tons of coal. The implementation of the second stage of the Clean Air Act (1990) caused demand for clean coal to rise quickly. The C&NW struggled to upgrade capacity to dual track, resulting in numerous failures on the line in 1994, and eventually Union Pacific's purchase of C&NW in 1995. The UP spent 855 million dollars over the next five years expanding capacity over its entire network to handle coal shipments from the PRB. By 2005 the Joint Line capacity had grown to handle an all-time record 325 million tons, and was either dual or three track capacity for its entire length.