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Illinois Live Steamers!
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Illinois Live Steamers!
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| ILS Bridge Project - Part 3 or... Lattice Entertain You By Carl Baskin Bridge building continues. With the cross spreaders welded between the bottom side truss members and “X” bracing welded at the ends, there are only three more matters to take care of on the bottom: 1) add some decorative gusset plates on the end corners, 2) weld in some cleats to bolt the bridge decking on and 3) weld in two (2) lengths of 2” high by 3” wide angle. These angles will carry the bridge ties and rail. Topside work continues as cross spreaders were cut and welded in five (5) locations on the upper arch truss members. Some of these had gusset plates attached before final welding in place. The end spreaders will have their gusset plates installed after all the latticework has been completed. In the meantime, lattice flat stock parts are measured, cut, fit and welded. Not only are these decorative, they also provide side-sway stiffness. The little pieces take as much time (if not more) than the larger pieces, so progress seems to have slowed down, but the bridge project is still moving along nicely (see photos #30 & 31). While some members may be concerned about bridge carrying capacity or load factor, “Spiner’s Rule of Thumb” states “an inch of good weld should carry 1000 pounds”. When you consider a load of two (2), 1500 pound, Northern type locomotives on the bridge, calculations show there will 150 pounds (max) at any joint. I think the bridge structure can easily handle that! (see photos #32-34). After all the latticework has been completed (5 places total), there will be four (4) “X” braces welded in across the top of the arches. Gusset plates will be welded in place on the upper end corners as well. Soon, it will be time for sandblasting, priming and painting. The last photo shows “the master bridge builder”, Chris Kamin, standing inside the bridge (photo #35).
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