3.5 Steel Trestle √
Although the Greystone had a custom laser-cut wooden trestle, it no longer exists. Then I thought about using a brass pin-connected truss bridge left over from the Black River & Western, but it was entirely too large, overpowering both the layout and especially the trains that would be using it. So I switched to a steel trestle, which is far more common in New Hampshire. I started with plate girders from Micro Engineering, and some Vollmer truss bridge parts.
However, when I started planning the piers, I felt four were too many, so I rebuilt the bridge with all new components: plate girders from Atlas N Scale through plate girder kits, and lattice from Micro Engineering HO Scale generic lattice parts—by good fortune, the largest of which measured 9mm wide. The Atlas parts required top and bottom cover plates and end stiffeners, which I made from 0.015" x 0.060 Evergreen styrene strip stock. The result (above) was better-looking and had only four spans instead of five.
Next up, the piers. I waffled back and forth between stone and steel several times, even building some steel pier components, until I finally settled on stone. But the Chooch piers I had on hand were massive space pigs, so I sliced them roughly into thirds on a (full-size) table saw, and glued the end parts together with CA. I did the same thing for the abutments as well. A light touch-up with a Dremel grinding bit hid the seams.
Afterwards, I sprayed the stone parts with a mix of light and dark grey primers, followed by an India ink wash, then a mortar wash. And the bridge girder assembly was sprayed with a mix of dark grey and ruddy brown primers, followed by a Rust-All wash. Bridge shoes are simply small squares of styrene—not unlike the squares of thick steel often used for bridges of this type in life. Finally, installation of Code 40 guardrails completed the bridge on 21 June 2020. Click for an enlargement.
Reference Image
I used this bridge outside of Gilead, New Hampshire, as a general guide:
