Saturday, May 6, 2017

Building another crossing with two bridges

 I have a major crossing that goes over your head as it crosses the aisle with the branch going over the aisle and the main line at an elevation of about 76 inches. To do this, I have an Overland pin connected truss bridge and a plate girder ridge. The truss is made in China and I have to build the plate girder. The truss has a walkway that I cannot use as it is not prototypical for my area so I had to remove it and its braces from the bridge. You have seen the painting process in an earlier posting. The next issue was making the track structure for the bridge. You cannot work in the bridge as you cannot reach the track so I needed a way to make the track in a fashion that fits into the panels of the truss. After carefully measuring the dimensions of the panels, and computing the number of ties with the spacing I desired for my recently stained ties, I came up with the jig you see here with some ties on it.
Every tie has to be spiked (the guard rail will come after some painting is done) and this was a problem with every thing wanting to move around. I am using a six foot long section of code 125 rail for my running track and that was sure wiggly. You can see the spacer for the girder that delineates the panel onthe bridge.  
 I set the spacing with the dimension of my tie plus a 3/32 stripwood spacer and that gave me 22 ties per panel. I eventually learned I had to tie that all together by gluing the end timbers to the ties to hold that panel in place. I could only do two panels at a time and one panel was from the previous build so it was slow going. The most important things was to maintain that panel spacing. You can see the jig has guards on top and bottom to hold the ties in alignment easily.
 After a while it became much easier to do but we had several false starts until the process became self evident.
 You can now see the complete deck with guard timbers and rail. Now, I have to build the girder bridge, and add the guard rails.
It's now Easter and another grandson loves to run his trains as well. All work stops for a while.

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