Paul,
This has 3 diagonal elements of totally different feel, actually 4 if we add the sky.
Any chance there's detail of clouds or s gradient hidden in the sky.
Did you also try a more contrasts expression in the wooden wall with peeling paint. I'd imagine that there might be further rich variation in tonalities that might be in the original raw file?
Anyway, each time you share a picture of the bridge I am so happy to see you searching for a small area to study and bring that to us to enjoy.
Thanks,
Asher