Märklin Engine

Marklin the Mystery Engine is a black tank engine who was used for moving background rolling stock in Season 1.

Bio
Marklin is a black tank engine, who was being used for moving rolling stock in the background in the first season of "Thomas the Tank Engine & Friends". In Tenders and Turntables when Gordon sees James spinning on the turntable, there are some trucks moving alongside him. These are being pulled by Markin. Also, in Off the Rails, the mysterious moving lights in the background when Gordon is being rescued from the ditch, it is most likely that Marklin was the engine who had those lights.

Evidence?
The real evidence that Marklin the Mystery Engine was used for background shots for Season 1 is the crew members' dedication page on the Sodor Island website. It has a photograph showing Thomas by the signalbox, James about to go onto the turntable, and Gordon alongside the line of trucks being pulled by Marklin.