The Coconino sun., 1921-01-28
HOW SUSPENSION BRIDGE
 WILL BE BUILT AT CANYON

of animal transportation from the south to the north rim in Grand Can yon National Park, Arizona, the Ma tional Park Service of the department of the interior is to build suspension bridge across the Colorado river. The north side of the park, or the north rim as it is called, is today practical ly unvisited owing to the difficulties attendant to getting horses or mules across the Colorado. Those who have made the long journey from railroad points in Utah have been tremend- ously impressed with the scenic gran deur of the north rim. It is about 1 300 feet higher in altitude than the south rim and the great chasm viewed from this side reveals new and al- turing aspect. With the construction of the suspension bridge rim-to-rim travel is destined to become one of the most fascinating of park trail trips.
 The construction of the bridge pre- sents number of problems, one of the most interesting of which is the transportation of the bridge materials down the trails to the construction site. The bridge will be thrown across the river in the Granite Gorge, which at this point is approximately APO feet wide with almost perpendicular sides. The span length of the bridge will be about 800 feet and will be sus- pended 40 feet above the general water level and at least 13 feet above the highest indicated water level. The trail distance over which the bridge material will have to be packed is about 10 miles, descending into the canyon distance of slightly over one-half mile. The trails are tortu- ous, having switchback after switch back; and in many places grades ex- ceed 40 per cent.
 In designing the bridge it was nec- essary to secure a structure which would be light and at the same time have sufficient strength to accommo- date the travel and to have the units of such size or weight that they could be packed by mules down the trail. The main cables are to be of special tramway blow steel, each weighing between 700 and 800 pounds, requir- ing four mules to transport it. It is planned to divide the cable into four pairs of coils, one pair being placed on each mule with an intervening length of cable of about 20 or 30 feet. Each mule will be in charge of a pack CT and the intermediate men will, in addition to leading the mules control the slack of 20 or 30 feet of cable so that they can successfully negotiate the switchbacks.
 The floor system of the bridge will be suspended from the main cables by special 3-8 inch steel wire ropes, plac- ed every six feet apart, which at at tached to the floor beams by 3-S inch steel stirrup rods every three feet apart. The hanger cables will be packed in small coils and the stirrup rods will be folded on themselves so that they will be of sufficient length to permit packing. The floor system will be cut into pieces not more than 9 feet long in order that they can be readily packed, but even timber of this length will make it difficult and interesting work for the men in charge of the pack mules to success fully guide them down the trails.
 The bridge will be five feet wide "iIl Suaiu idiiS Ol HtdV. fHeSn wire and because of the wind play and vi- bration which may be expected in a bridge of this length impoundinp gates will be placed at each end so that only one mule or horse will be permitted to cross at time. It may be necessary at first to blindfold the animals, but after they have made the trip onec or twice they will become ac- customed and will not hesitate to cross. The bridge vii cost in the neigh borhood of $13,000 and contracts have already been entered into for it's con- struction and it is expected that tour ists may be permitted to cross before the close of the 1921 summer season. Two additional bridges are planned at different points on the Colorado with in the national park area, which are component parts in the ultimate de- velopment of north rim travel.
 If you want real thrill-to ride a blindfolded mule over a 800 foot bridge suspended forty feet above the muddy torrents of the Colorado river, with scenery of unrivaled grandeur on