That Eagleroost & Koontree locomotive is a mongrelish cross between something Welsh and something Coloradish.
E. L. Moore remarks on the lineage of E & K locomotive #5.
After a little searching based on E. L. Moore's remark that this locomotive is largely scratch built over a Kemtron Teakettle frame, it looks like he used Kemtron's brass HOn3 Teakettle 0-4-0 kit for the running gear, boiler and most of the structure forward of the cab. That's the American, or more specifically in Mr. Moore's terms, the Coloradish part of the model :-)
He didn't use the kit's cab but built his own, and it does resemble narrow gauge locomotive cabs of Welsh heritage. I can't point to a specific prototype, but it seems to capture the general look of cabs on those machines. You can also see that he added a set of wheels under the cab's back end.
Mr. Moore also noted that it has a couple of interchangeable pilots, making it a general purpose workhorse on the Wales-orado mountains of the Eagleroost & Koontree.