Dylan,
Looking at those other three, and seeing the railroad and location, this Miller Creek span is most likely just a short version of the others. And they are clearly Warren trusses. That makes me even more confident this one is classified correctly.
Like this one, they have the mid-panel bracing like a Baltimore only on the end panels. The mid-panel brace on the rest of the web is horizontal, and only between "V" shaped members and NOT the center "A" shaped. Odd.
Fmiser:
What do you think of these three bridges?
http://bridgehunter.com/ia/poweshiek/bh55076/
http://bridgehunter.com/ia/hardin/bh51824/
http://bridgehunter.com/ia/marshall/iowa-river-railroad/
They are a stretched version of the short span. Very unusual and interesting.
It's a short span - so there really isn't much difference between a warren and a pratt. Because the vertical are all similar mass, I would tend to classify it as a Warren with verticals.
The sub-dividing of the end two panels is like a Baltimore - but the horizontal brace in the center two panels are not a strictly Baltimore stye dividing.
So what is it? Good question! I think the existing classification is accurate, though not the only one that could be used.
I did expand the text description to better describe the truss.
Even to the untrained eye, like mine, they are definitely a unique and unusual design. Two north of Eddyville are still in service, while this one and Miller Creek #4 are abandoned.
You should check out the UP - North Skunk River bridge. They took the same unusual design and stretched it.
http://bridgehunter.com/ia/poweshiek/bh55076/
I have not photographed the two bridges north of Eddyville or the one over the Skunk River. Starting to get the bridge photo bug again. I'm going to have to get back out in the field soon...
Labeled here as a Warren, but I'm thinking a 4-panel Baltimore with the unusual appearance of a Queenpost truss within. Looks like a pony sitting inside of a thru truss!
Thoughts?
Fmiser:
Thanks for your response!