Source: Mining and Scientific Press, 1885.
The Isthmus of Tehuantepec was, for long, an interoceanic shipping option that was particularly attractive to the United States. From its perspective, the distance involved was shorter than the Panama option. However, due to elevation and land distance (roughly 230 km), canal construction was not retained as an attractive proposition. In 1884, the American civil engineer James B. Eads proposed constructing a transoceanic rail line between Salina Cruz (Pacific side) and Coatzacoalcos (Gulf of Mexico) that could carry whole ships. The goal was to build a six-track railway with three locomotives pulling ships across the isthmus in about 13 hours. The system was designed to carry ships of up to 10,000 tons into a wheeled cradle.
Although initially triggering interest, the project was abandoned in 1887 after Eads’ death. The interoceanic railway was designed at a time when ship weights were still relatively light because of their wood armature. The growth in ship size and weight by the early 20th century would have made such a project increasingly marginal. Still, the idea endured. The Mexican government considered a similar project in the 1940s, which could carry ships of up to 15,000 tons. Again, the substantial growth in ship size after World War II would render such an option impractical.