Flynn Alternate Basis

Following Belle's rework, I've been nudging Flynn around like a pile of cold mashed potatoes trying to figure out what to do with him. I considered just making him a regular fire truck, but Sodor is a place where having at least one road-rail fire engine would probably make sense? So I thought I'd pick a different, specific basis.

How does a Morris C8 vibe? To my knowledge, they were repurposed into fire engines post-war, and would be light enough for a road-rail modification to be feasible. (Plus, it opens up some fun opportunities backstory-wise.)