The Texas Mexican Railway International Bridge is an international railway bridge across the Rio Grande and U.S.-Mexico border between Laredo, Texas, and Nuevo Laredo, Tamaulipas, the only rail link between these cities. Owned and operated by CPKC, the single-track bridge is the busiest rail border crossing in North America. It is also known as the Laredo International Railway Bridge and Puente Negro (The Black Bridge).

The bridge opened in 1920. The approach to the bridge on the side of the United States was controlled by the Texas Mexican Railway (Tex Mex), which had been owned by the Mexican Government since the turn of the century. The approach to the bridge on the Mexican side would also come to be fully owned by the when all railroads were nationalized under Ferrocarriles Nacionales de México (N de M, English: Mexican National Railways) in the late 1930s.

Tex Mex was sold to Transportación Maritima Mexicana (TMM) in 1982. 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.

Canadian Pacific Railway purchased KCS in December 2021 for US$31 billion. On April 14, 2023, the railroads merged to form CPKC, the first and only to directly serve Canada, Mexico and the United States. 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.

The bridge is the busiest rail border crossing in North America. As of 2022, the bridge was operating at its maximum capacity of 26 trains per day. Further growth was limited by the need for customs and safety inspections at the crossing. On October 31, 2022, KCS broke ground on a second parallel bridge, which will double the capacity of the crossing, and allowing each bridge to be focused on a single direction of traffic. The bridge is expected to be completed in October 2024.