Never did say thanks for the inspiration. This is what I did on my xmas vacation. The prototype is a BNSF bridge in Sioux City IA: http://www.flickr.com/photos/bluebird218/2647586855/
Although I don't have any use for long spans, I am kitbashing 150' long Warren truss bridges that are correct for the U.P. in Weber Canyon out of incorrect Central Valley Pratt truss bridges. I'm sorta in the planning stage and making tools to modify the fragile parts of this kit. The most difficult part so far is deciding how far I want to go to make them "exactly" as the bridges prototypically are, or "close enough". I seem to be favoring the "close enough" mindset, as anything more would essentially cause me to simply scratchbuild the bridges rather than kitbash 'em. All I can say is "Thank you MicroMark and Archer Transfers for resin rivets!!" Cheers! Bob Gilmore
I started out just looking for a prototype that was the right length so that I could get the proportions right and make a plausible bridge. Once I found the prototype I got a little carried away and made an exact model after drawing it up from internet photos and google earth. But I haven't the patience for rivets and couldn't do the hand rails justice. The approaches are hacked Kato thru trusses that are grossly incorrect to begin with; I just wanted to finish the job and lowered my standards back to "plausible".
Anyone see Daryl Kruse's Mississippi River bridge crossing at Clinton, IA in the latest N Scale Railroading? It's May - June 2012 issue. That is really a nice one. Three spans including a non-functioning swing bridge. About 5.5 feet (about 1.7 meters, I think). All pretty much scratchbuilt.
Nice bridge! It looks much longer than its scale 425 feet (32 inches). BTW, most bridges have a similar height to length ratio, and virtually identical arches, so they can be scaled up and down without too much concern, although the size of frame members has to be adjusted. Many modelers are put off by the lattice-work of the structural members, not realizing that many bridges since 1960 are built with solid members, sometimes of aluminum. For many years it's been cheaper to build a heavier bridge than to pay the labor to build the lattice-work. Nice to see another through truss built!
Russ, Most railroads would choose three short spans over one long span. They only chose long-spans when there was no other economical choice. Sometimes it's height over a navigatible river; sometimes it's ice that would tear away any mid-stream footings (ala Tanana); sometimes its just a deep gorge that makes piers unrealistic.
At 23.5" in N-Scale, this would classify as a long span bridge. I am developing a tutorial on bridge design for all and will feature the deck truss at Topock and the cantilevered deck truss at Canyon Diablo. Here is a quick sample of how the bridge truss will look. Since this is only the first of two trusses, it is taking some time to put this together. I did go nuts with the detail. The second photo shows all of the tie-plates I am putting on the vertical columns. If you guys want progress shots, I'll start a new thread and post there.
Here's another one, the Topock bridge will be amazing! I might need to extend may layout east of Barstow.... Regards, Otto
Wow! You are working at a way higher level than stryrene can go. Definitely interested in updates. And any suggestions for getting or building decent handrails like the ones in your proto photo.
