Glennock is a 'fankid' of Rheneas and Stepney. Don't ask me how that works, that's a question for the client. So I had to come up with a design that was halfway between Rheneas or the real life Dolgoch, a narrow gauge 0-4-0 built by Fletcher-Jennings, and Stepney, a real life LB&SCR A1 Terrier 0-6-0 tank engine. The client originally asked for a side tank engine, but I talked her into a well tank since it'd be easier to make her look like Rheneas despite being standard gauge.

My initial thought was to just find a suitable engine and make that the basis. And honestly, that could have worked. My original choice was a Beattie well tank

Maybe modified a bit to look more like Rheneas and Stepney.

And while I did still take some inspiration on the mechanical side of things from the Beattie, as well as a Class G standard gauge 0-6-0 designed by Fletcher-Jennings, Glennock ended up being almost entirely a one-off design based on Dolgoch and Stepney.

Rheneas and his real world counterpart, the Talyllyn Railway's No.2 Dolgoch

Stepney in the Railway Series and Stepney in the real world.

The boiler is largely a scaled up Rheneas boiler, and below the frames it is more like a Class G. Stepney's contributions were largely visible, like the Stroudley cab, and a livery pattern based on Stepney's Improved Engine Green.

The livery was a real headscratcher because it had to incorporate pale blue as the main color, Stepney's orange-yellow color, and Rheneas' red. Took a long time to figure out something that looked halfway decent. It didn't end up with a ton of red (no more than most british steam engines) but to be fair the mechanical side is a lot more Rheneas than Stepney.

I was kind of imagining this engine was a one-off industrial engine built by Fletcher-Jennings, with the Stroudley style cab being a later addition. (Perhaps she was not originally built with one)

(Though I think the client probably had something more supernatural in mind--i'm sure they can clarify in the notes.)