Two huge engines are required to negotiate the heavy ascent, and at last, when the top is attained, the train is 276 feet in excess of two miles above the Atlantic on the eastern, and the Pacific on the western side, respectively. The tortuous path of the iron road is revealed below in a graphic manner. It may be seen in no less than four separate terraces, rising in steps one above the other, the lowest being almost invisible, connected by huge loops, until it finally winds away and is lost in the dim haze of the horizon. The descent is a replica of the ascent--the same gradient prevailing, viz. 211 feet to the mile. No steam power whatever is needed to drive the train. It is travel by mere gravitation alone, held in check by the powerful air-brakes. Yet the railway is crossing the Divide at another point some miles to the north rises twice to an altitude exceeding 10,000 feet. This is on the extension of the original line from Pueblo to Leadville, where, after leaving the mining town, there is a tedious climb to Fremont Pass, where the track is laid 11,330 feet above the sea. A few miles to one side the line attains its maximum altitude, with 11,522 feet, at Ibex station, on a short branch road. After negotiating the Pass there is a sharp descent to Leadville junction, where another locomotive has to be hitched on to haul the train up a bank, rising 211 feet to the mile, to the summit of Tennessee Pass, lying at 10,240 feet, the highest point being gained in a tunnel, one mile in length, bored through the mountain peak. On the southern section of the system the line passes through some of the wildest and most impressive country it is possible to conceive, and time after time the constructional engineer was puzzled sorely as to the best route for the road. It overcomes the Divide through the Cumbres Pass. On the up-hill pull the railway skirts a towering mountain spur, making a detour of four miles to circumvent the obstacle, and then bursts suddenly into a strange country. Strange monoliths rear up on all sides their fantastically wind- and weather-carved sides, glistening weirdly in the sunlight. The line swings round these grotesque evidences of Nature’s handiwork in a sharp bend known appropriately as “Phantom Curve,” and then disappears into the depths of the Toltec tunnel, which is carved through solid granitic rock for some 600 feet. The peculiarity of this work is that it is carried through the crest, and not the base of the peak, for the opposite portal of the tunnel stands on the brink of a precipice which drops plumb a quarter of a mile into the valley.