Okay, so TF twitch asked me take a look at his Humble Sapphire-style 4-4-0 locomotive, the Tempered Stallion. I then put it side by side with my 4-4-0 to compare notes. This is the result! LDD file included!
About this creation
I liked his engine's boiler but I wasn't sure on how I felt about the 5 wide firebox. Aso, the boiler was like the Toy Story 3 train with it's sideways building of the boiler, which I had in real life in the past and wasn't very stable no matter what I did to it. So I substituted the tried-and-true Constitution Train Chase boiler instead.
The gold parts would have been very difficult to place and keep there in real life. I also fixed the magnetic coupler: the version originally used was the original 2006-2009 variety which were replaced in 2009 / 2010. (Please see here for a picture of the different coupler types: alpha.bricklink.com/pages/clone/catalogitem.page?P=91968c... )
The pistons also were a problem with the connection to the engine from Toy Story 3 being rather flimsy and breakable. I replaced them with a Tony Sava inspired design.