Owned and operated by CPKC, the single-track bridge is the busiest rail border crossing in North America.In 1996, the Mexican Government privatized N de M, and sold the Northeast Railroad leading to the bridge to Transportación Ferroviaria Mexicana (TFM), a joint venture between TMM and Kansas City Southern (KCS).At that same time, TMM sold 49 percent of Tex Mex to KCM, making both sides of the bridge a joint venture.KCS bought out TMM in 2005, integrating Tex Mex into its Kansas City Southern Railway and turning TFM into Kansas City Southern de México, giving the railroad full control of a route between the midwestern United States and a large portion of Mexico.One of the major arguments for the merger was that it would increase competition in the Chicago–Mexico corridor that had been dominated by Union Pacific and BNSF Railway.