Page:A Study of Mexico.djvu/52

42 or winding round a succession of mountain promontories—the "Vera Cruz and City of Mexico Railroad" has been constructed; "rising" or "falling"



—according to the direction traveled—over four thousand feet, in passing over a circuitous track of about twenty-five miles; and of which elevation or depression, about twenty-five hundred perpendicular feet are comprised within the first twelve miles, measured from the point where the descent from the edge of the plateau begins. To overcome this tremendous grade in ascending, a sort of double locomotive—comprising two sets of driving machinery, with the boilers in the center, and known as the "Farlie" engine—is employed; and even with this most powerful tractor it is necessary, with an ordinary train, to stop every eight or ten miles, in order to keep up a sufficient head of steam to over-come the resistance. In descending, on the other hand, only sufficient steam is necessary to work the brakes and counteract the tendency to a top rapid movement. As an achievement in engineering the road has probably no parallel, except it may be in some of the more recent and limited