David Poole is namely responsible as one of the model makers working through the programme's years but especially played his part in the Jack and the Pack spinoff shows.
His website presents not only a picture of Buster the Steamroller, but also the aforementioned character's scaled down body.
The description attributing the screens doesn't mention Thomas & Friends, nor the character of Buster.
Poole, also known to design and engineer various aspects of model making has an extensive CV ranging from feature films, namely Mission Impossible II, Clash of the Titans and more.
Thanks to Troublesome Truck for the alert.