That's impressive. Good light and angle, and on a hand coated plate! I have to wonder about this vehicle - why was it left there, and who was motivated enough to extract the engine!
It's a film of vitreous sand bearing a film of silver-based emulsion. I call it an analog film process, regardless of the substrate. (But I didn't say it with that detail because I was keeping it short -- and my caffeine infusion hadn't kicked in .... )
I always love your plates, and this just strikes a resonant chord with sustaining positive feedback. Like @DWThomas , I like anything that smacks rust immortalized on film.
The shimmering soft reflective light off the bumper is amazing here.