Pratt Bridge HELP PLEASE

Here is a scale model bridge made of brass.

I am looking for the measurements of the main support beams. The square stock that is used to make the top and bottom rails. Any other information would be great also as I am going to build one myself if I can get the specs. I know the length, height, and width.

  Pro Hobby,

   Is the bridge you show O-Scale (1/48)? Who made it? I have been looking for something similar.

Douglas

Atlas O has a nice pre-built thru truss bridge in both double track and single track.

Plastruct has a nice kit for a thru truss bridge as well. I think just a single track.

Thanks for the information. But I plan on building one. Cause I can not afford one of there's at this point and time.

I built modified Plastruct trusses making them deck trusses since I couldn't handle the through truss due to curves in the approaches. The plastruct main I-beam girders are 1" high by about 1/4" wide. The uprights were 1/4" square h-beam. The diagonal bracings was 1/4 X 1/8" I-beam (or thereabouts).

A realistic way to do this out of wood without making it a clunky contraption would be to fabricate your own H and I beams using thin aircraft ply carefully cut with a hobby knife and straight edge. These ultimately would be very strong, light and have the same look when painted as steel structural members.  

What makes these bridges so beautiful is that the parts are thin and delicate with their strength coming from the relationship of the parts and the networks they form. An I-beam created from air craft ply could actually be stronger and less apt to bend than a solid wood member of the same thickness. Look at what their using for joists in new home construction. Engineered lumber is more rigid than traditional solid wood joists.

Thank you so very much. That was the information I was looking for. I know I can build it, just needed information. I will be posting on here as I go so everyone can give input. Thank you again! I also love your post you put up of your build, there is a lot of what you do that I hope someday to copy if that's ok with you?

Glad I could help...Even scratch-building, if you wanted to build it entirely of Plastruct, it will probably run over $100 for the raw materials. I spent that much just on some pipe and fittings for the boiler house. Scratch building isn't always cheaper, but it's always more creative.

I plan on building it out of some Oak I have laying around.