A regular railroad, not a rail canal as GP was suggesting. Such a rail canal was suggested for the Isthmus of Tehuantepec, though (the narrow waist of Mexico):

A regular railroad, not a rail canal as GP was suggesting. Such a rail canal was suggested for the Isthmus of Tehuantepec, though (the narrow waist of Mexico): https://en.wikipedia.org/wiki/Isthmus_of_Tehuantepec#/media/File:Mining_and_Scientific_Press_-_March_28_1885_-_Interoceanic_Ship_Railway_(206).png https://en.wikipedia.org/wiki/Isthmus_of_Tehuantepec#/media/...