I haven't had a lot of time for modeling so far this year, and what time I did have, has mostly been spent refurbishing older models. The newest structure is a through, plate girder bridge. Until now I've just had a crude temporary bridge made of wood, which has become badly warped:
I built a permanent replacement for it. My previous plate girder bridges were all made using a structural fiberglass material called G10. This time, I wanted to try making it out of Sintra. I used 6mm Sintra for the deck and sides. The interior braces were made from 1mm Sintra. The rest of the details are styrene. I got a bit lazy on this bridge and decided to leave off the rivets -- where it's located, no one can get very close to it anyway. The underside of the bridge is strengthened with three lengths of 1/2" square acrylic tube, plus three sections of extruded aluminum angle for good measure.
I sprayed it with red primer followed by gloss black. Then I weathered it with a thin, alcohol wash of gray acrylic paint. Then I used RustAll to create reddish rusty streaks. Next I used Sophisticated Finishes' "Iron" and "Rust Solution".
Two of my earliest structures on the layout were really starting to show their age. The paint was faded and worn (beyond the intentional weathering). The clear plastic used in some of the windows had yellowed, fogged, and warped. Slide cover glass used in a few places had broken or fallen out. A couple signs were faded, and both structures had minor damage caused by a raccoon. One of the buildings still had incandescent "grain of rice" bulbs, which I wanted to replace with LEDs. Here are the "before" photos: