Due to various trackage and locomotive failures on the Joint Line in late 2004 and early 2005, the line failed to deliver the amount of contracted coal supplies, and electricity rates increased by 15 percent. Coal customers threatened to evaluate alternate sources of energy and transportation, including the Arkansas Electric Cooperative Corporation. As a result, the expansion of the Dakota, Minnesota and Eastern Railroad line was approved by the Surface Transportation Board. In 2006 UP and BNSF announced a $100 million investment to provide three track capacity for the entire length of the Joint Line plus a fourth track added over the steepest sections, including Logan Hill. These improvements will enable the Joint Line to handle over 400 million tons of coal.