In 2007, the line gained publicity when a train hauling parts of the Space Shuttle solid rocket booster derailed on an overloaded bridge weakened by heavy rains.

On June 28, 2023, Canadian Pacific Kansas City and CSX Transportation announced the intention to jointly acquire the MNBR line.

Currently, CSX traffic going to Mexico is exchanged with the Union Pacific Railroad in New Orleans, who then takes it to the cross-border gateway in Laredo, Texas, where it is delivered to CPKC.

[9] Kansas City Southern, one of CPKC's predecessor railroads, attempted a joint purchase with CSX of the MNBR line more than two decades ago.

The deal was scrapped for fear of angering BNSF and Union Pacific, the two dominant railroads in the west, who did not want CSX or Norfolk Southern to do business with KCS.

[9] MNBR's Western Line, once acquired by CPKC, will be renamed Haverty Subdivision, in honor of former KCS CEO and President Mike Haverty, the original driver of the idea to acquire MNBR more than two decades ago, to tie the KCS and CSX rail networks.