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Pacific Coast Railway bridge No. 5


the two double side trusses were then constructed in a sandwich-like fashion from appropriately-sized, pre-stained stripwood. First came one of the pre- fabricated ironwork assemblies on the bottom, then


the pre-stained wood


members were laid over the top with the proportions maintained by the jig. Since the wood was pre-stained, gap filling cyanoacrylate cement was ap- plied with a toothpick at the joints. A temporary “keeper” running the full length of the truss bottom was tack glued with rubber cement to the bot- tom of the wooden vertical members to maintain the shape until the whole truss could be assembled. Then two more soldered-up ironwork assemblies were laid over this, followed by the sec- ond set of wood truss timbers and the final set of the ironwork. With the two double trusses now com-


plete, it was time to assemble the whole bridge structure. To insure that the two sides would be both parallel and at right angles, a cardboard box was built up with the edges and corners taped to- gether. This was used as a core around which the side and the top members were assembled. Having the box dimen- sions exactly match the inside of the bridge was critical to maintain accura- cy. The side double trusses were gently taped to the box, then the cutting and fitting of the top cross bracing proceed- ed. At best this was tedious. The whole structure was turned up- side down and the temporary “keepers” were removed. Next came the iron bridge shoes and the doubled 10″×20″ cross beams to carry the stringers and track structure. I used contact cement for these connections. To hold a Howe truss together, pins go through the eye rings of the tension rods and chords. To model these I in- serted a length of wire through the rings of the outer layer of the assembled ironwork pieces, the outer bridge shoe, the two middle iron members, the inner bridge shoe and, finally, the rings in the inner ironwork assembly. This was done at each location where these parts came together, and any holes that were filled by solder or paint were opened up. See the plans and photos. Given the fragili- ty of the model at this point, I left the cardboard support box in place until I was ready to glue on the stringers. Separate from the truss itself, the scale 16″ deep stringers were laid out per the drawings and were made the full length of the bridge to provide structural integrity. (An actual bridge floor would have shorter timbers with the butt joints staggered, the through- bolts and thimbles tieing things to- gether.) For this model we glued a rec- tangular brass tube, ¹₈″ deep by ³₈″


54


The completed model at the west end (above) shows shoring details and supplemental brackets for the various pipelines. Integral to the bridge scene is the water, in this case involving three pours of epoxy, to obtain coloring depth and ripples (above and right), and the subtle weathering, which in fact consisted of leaving the wood to age naturally and then occasionally whitewashing the ends of the structure for visibility.


wide and running the full length of the bridge, between the middle stringers to provide additional real weight carrying capacity for the delicate structure. The tube’s bottom and top were painted black to reduce its visibility, and the top would eventually be covered by the track and plank walkways. The next step was to remove the cardboard former, insert the stringers properly spaced, and glue them to cross beams. The bridge was test fitted, then installed on the piers and base to await construction of the track and final de- tailing and weathering.


Track The track was built as a single unit


44″ long so it could be installed onto the previously constructed trestle and bridge components. It would have to be completely detailed and weathered pri- or to insertion into the delicately framed bridge.


While both fabricated track with plastic ties (Micro Engineering) and separately cut wood ties (Campbell, Kappler and others) are available, I chose to cut my own ties by ripping basswood to the correct size on a table saw sized for modeling and make up my own track. In this case the ties were cut to scale nine-foot lengths. The ties were distressed, stained with alco- hol and ink, then weathered with ap- propriate oil and rust colors. I made a jig where the rails could be inserted with the bases facing up. The jig also had a backstop for correctly locating the ties so they were centered on the rails. Pieces of PC board ties were also


cut and soldered onto the rail every four inches (appropriately cleaned, fluxed and tinned, of course) to main- tain spacing and the overall straight- ness of the rails without using spikes. The copper surface must be severed to avoid a short circuit between the rails. The next step was to use the jig to in- stall wood ties between the PC ties. I found I could use Barge contact cement (other brands would also work) and place the ties by eye for a relatively even spacing of one tie per each twelve scale inches. Since the rails slide in the jig grooves, it was a simple matter to keep moving the track forward and in- stalling the next segment. After the tie installation was com-


plete, the track structure was removed from the jig and flipped upright to add the plank walkway and the 6″×8″ guard timbers at the ends of the ties. The Pacific Coast did not use guard rails at this location. Again, the timbers were pre-stained and distressed with a few splits and knot holes prior to installation. Nut- bolt-washer castings were placed on the guard timbers at every fourth or fifth tie, and adequate wheel clearance between the rails and walkway planks was checked as the planks were glued in place.


Now comes a unique and interesting part of the model construction. After the railroad was complete, Union Oil Company (more recently known as Un- ocal) worked with the Pacific Coast Railway to construct a second pier to load their oil tank ships, and they needed a way to transport the crude oil


SEPTEMBER 2012


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