Autumn on the Chelatchie Prairie Railroad. Crossett Western saddle-tanker #10 rumbles across the high bridge, spanning the East Fork of the Lewis River on a beautiful fall day. The bridge seen here is a most interesting one, featuring a somewhat unusual Pratt Deck Truss on concrete abutments for the actual river crossing, and wooden trestles on both approaches, one of which is visible here. Folks may wonder what a Pratt Deck Truss is. A truss of course, is a structure built of triangles, and there are many different ways in which those triangles can be configured and loaded. The Pratt Design uses vertical members, and diagonals that slope down toward the center of the structure. It was named for designers Thomas and Caleb Pratt, back in the mid-1800s. The bridge seen here is referred to as a Deck Truss, because the bridge deck goes on top of the truss, instead of through it.
Photographer's note: This is one of those photo locations that really demonstrates the advantage of a raw image. The camera position is in deep shadow, the dark subject is back-lit, and the sky overhead is bright with white cirrus. Shoot a JPEG here, and you'll never have the latitude in post to capture both the shadow detail and still have the sky looking realistic. If you're faced with a shot like this, shoot raw, even if you've never worked with raw before. You'll not regret having that image to play with later.