Thereupon he evolved a plan to throw heavy iron girders in the manner of rafters across the gulch, to anchor their ends to the solid rock, and then to suspend the bridge carrying the metals from this structure in such a way that one side abutted against the wall. The more he pondered, the more convinced he became of its practicability, despite the fact that it was something entirely new to railway engineering. Being intimately acquainted with the late Mr. C. Shaler Smith, who at that time was one of the foremost consulting bridge-engineers in the country, he communicated his plans to him. The consulting engineer was interested, and arranged to accompany the designer to the site to judge the feasibility of the scheme at first hand, and after acquainting himself with the prevailing conditions. As a result of this investigation, Mr. Smith concurred in the method of spanning the gap, and there and then the arrangements for carrying out the work were commenced. It was realised that the task was somewhat delicate, and Mr. Robinson accordingly entrusted the preliminary operations to Mr. J. O. Osgood, who was appointed Division Engineer on this section of the railway. Mr. Osgood carried out the whole of the surveys for his chief personally to facilitate the accurate design and details of the whole structure. [Illustration: THE RAILWAY TWO MILES ABOVE THE SEA The Denver and Rio Grande at the summit of Marshall Pass. The sinuous route of the line may be followed for miles.] The surveyor related to me that when he first entered the canyon no one had ever traversed the gorge at that point, except on the ice, for the simple reason that it was impassable. Nor could one get across by clambering along the rock face where the line was to go, as it was too steep. The situation was first reconnoitred from all practicable points of vantage. Then, in order to complete the essential preliminary work, he caused a narrow pathway--nothing more than a ledge, from 12 to 18 inches in width--to be hewn in the cliff above the site, from which he made his final surveys. [Illustration: A “DOUBLE-HEADER,” CLIMBING THE CLIFF OF ANIMAS CANYON ON THE DENVER AND RIO GRANDE RAILWAY]