Just thought I’d post a few pictures of a pair of bridges I scratch built some time ago. Each rivet was put in by hand and they were made from strip styrene, enjoy.
Photos are great, but how about some discussion on which parts you acquired and used to build the bridges and how you went about building the bridges. Did you follow a set of plans or just work from photos of the prototype?
I used Evergreen strip styrene strips and sheets for the actual bridge parts themselves. The rivets were made by Tichy I believe.
As for the design of the bridges, I followed images in the Kalmbach book Model Railroad Bridges and Tressles. I started with the smaller bridge as a test to see if I could work with the styrene and did the larger bridge second. These were my first experiments with scratchbuilding with styrene.
I worked on one side at a time, cutting pieces out, drilling holes for the rivets, inserting and cutting off the rivet backs, then fastening the parts together. All told, I think I built the pair of bridges over about a two week period of picking away at them. I still need to add some weathering to them both.
That’s some really clean crafsmanship on the truss bridge bracing and rivets, but the deck of the bridge looks way too spindly to actually support the weight of a train over it, and there’s absolutely no lengthwise beams to support the ties for the track.
While that’s very nice workmanship, especially on the truss bridge, I have to agree with Chris about the design of the deck. I also wonder about the truss layout and how it doesn’t directly correspond to the arrangement of the cross members and braces of the bridge’s top. It seems that the more logical (and I’m guessing, as I"m no structural engineer) the stronger option would be to adjust the length of the truss panels to match those of the bracing on the top. This would result in a three-panel Pratt truss, with the centre panel having diagonals running in both directions. The design as it stands places the vertical forces within the side structure at points other than the intersections of the horizontal bridge members.
Although it’s not overly clear in the photo below, the truss structure (top, sides, and to some extent, the bottom, supports cross girders (floor beams) at the bottom of each vertical member. These, in turn, support longitudinal girders (stringers) which provide support for the track.
If it would be of assistance, I can remove the bridge and take a photo of its underside.
Sorry, Forge, I took the photos almost immediately after you requested them, but photobucket appears to be having some difficulties, as I can’t upload them. I’ll post them as soon as the issue is resolved.
Unless you are a structural engineer I’m going to give you a “TEN” for a job well done. [(-D] Even if you are, your model train is not going to fall in the creek.
That is one fabulous looking bridge (and scene). Your modeling skills are excellent in so many facets of this hobby from rolling stock, locomotives, buildings and bridges. That is why I always click on your posts. Help I’ think I’m becoming a groupie. [swg]
I have said before that doctorwayne should be permanently banned from these forums. He is too good for the rest of us. He simply doesn’t belong. [(-D][(-D][(-D]
