A First For Me - Britt Allcroft

IIRC, that was the "in between" coach that came with a set of powered Splatter and Dodge. I think that was before HIT Entertainment was the primary producer/distributor of Thomas and Friends. That would place it in the era before the HIT Toys version of Trackmaster and around the time of "Thomas and the Magic Railway".

EDIT: WoodWheel92 beat me to the explanation!