Arizona republican., 1921-01-24
PARK SERVICE ID BUILD SUSPENSION
 BRIDGE IS CANYON

To- permit tourist travel by means of animal transportation from the south to the north rim in Grand Can yon National park, the national park service of the department of the Ihts~ rior is to build a suspension bridge across the Colorado river. The north side of the park. or the north rim, as lt is called. it today practically unvisted owing to the difficulties attendant lo getting horses and mules across the Colorado Those have made the loilS journey from railroad points in Utah have been tremendously impressed with the scenic grandeur of the norlH rim. It is about 1,50O feet higher Ill altitude than the south rim and the great chasm viewed from this slde reveals and new and alluring aspect With the construction of the suspen- sion bridge rim to rim travel Is des- tined to become one Of the most fascinating of park trail trips. The construction of the bridge pre- sents a number of problems, one or the most interesting of which is the transportation of the bridge mate rials down the trails to the construc- ton site. The bridge will be thrown { across the river in the Granite Gorge, which is approximately APO feet wide with almost perpendicular sides. The span length of the bridge will be 1 about 500 feet and will be suspended i 40 feet above the general water level. 1 The trail distance over which the l bridge material win have to be packed | is about 10 miles, descending into the canyon a distance of slightly over one half mile. The trails are tortuous. hay I ing switchback after swftchback. and 1 in many places grades exceed 4O per cent.
 In designing the bridge 1t was nee
 
 | 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 be- tween TOO and 500 pounds requiring 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 packer and the intermediate men will, in addition to leading the mules. control the slack of 20 or 80 feet of cable so that they can successfully negotiate the switch
 backs.
 The floor system of the bridge will
 be suspended from the main cables by special three eighth inch steel wire ropes. placed every six feet apart, . which are attached to the floor beams by three-eighth 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 suf- fieient length to permit packing. The [ floor system will be cut into pieces not more than nine feet long in order that they can be readily packed but even timber of this length will make } 1t a difficult and interesting work for l the men in charge of the pack mules to < successfully guide them down the s trails
 l The bridge will be five feet wide e with guard rails of heavy mesh wire s and. because of the wind play and vi- 2 bration which may be expected in a 3 bridge of this length. impounding gates
 will be placed at each end so that only ! one mule or horse will be permitted to [ cross at time. If may bo necessary
 at first to blindfold the animals. but
 after they have made the trip once or i twice they will become accustomed
 and will not hesitate to cross. The
 bridge will cost in the neighborhood oi
 S1S,e00 and contracts have already
 been entered into for it's construction
 and it is expected that tourists may be ! permitted to cross before the close oi J the 1921 summer season. Two addi- o tional bridges are planned at diffeent l. points on the Colorado within the ma
 tional park area. which are componen; ' parts in the ultimate development oi
 north rim travel
 Q If you want a real thrill--to ride 2 = blindfolded mule over a 5o0-foo - bridge suspended 40 feet above tn I muddy torrents of the Colorado river ,s with scenery of unrivaled grandeur or IF every hand-plan visit to the Crane If Canyon National park.