To its north, Mexico shares a border with the United States that is 3,169 km (1,969 mi) in length. The two countries share the same track gauge of1,435 mm (4 ft 8 12 in), with multiple links. 

To its south, Mexico shares an 871 km (541 mi) border with Guatemala and a 251 km (156 mi) border with Belize. There is an inactive link with rail transport in Guatemala at Ciudad Tecún Umán in Ayutla, San Marcos, with a break of gauge (1,435 mm (4 ft 8 12 in) / 914 mm (3 ft)). Mexico has no link with rail transport in Belize.

Class I Railroads
Mexlist : free electronic community for the exchange of knowledge about the Mexican railways.

Map of Mexican Railroad (by Ferromex)