I've especially read the specifications of Stepney's basis including his wheel configuration, number of cylinders, boiler pressure, drive wheel diameter, ad especially his exact top speed that happens to be approximately 60 MPH as I've been doing my research very carefully by reading my Smithsonian train book!
I'm personally pleased to see Stepney the Bluebell Engine in this video since he'd been mentioned as the very first engine to escape to the Bluebell Railway, and there's absolutely no doubt he especially had a book written 'bout him that was adapted during the show's 4th season! He certainly has a lot in common with Thomas the Tank Engine since they were both built by the exact same railway less than a whole century apart!
I've especially wanted to mention that I personally saw Dukedog #9017 certainly has a wheel configuration of 4-4-0 meaning a total of exactly 4 leading wheels, a total of exactly 4 drive wheels, and especially not a single trailing wheel meaning it's got an American wheel configuration!
Stepney the Bluebell Engine had been mentioned by the narrator to have been built in the exact same year as no.54 Waddon as seen in my Smithsonian train book!