The Ferrocarril del Istmo de Tehuantepec, also known as Ferrocarril Transístmico or simply Ferroistmo, is part of the Interoceanic Corridor of the Isthmus of Tehuantepec, owned by the Mexican government, that crosses the Isthmus of Tehuantepec between Puerto Mexico, Veracruz, and Salina Cruz, Oaxaca. Wikipedia