That looks sort of like an engine built by Ed Alexander built that's shown at the TCA Western Division site - the caption under the model states Alexander built a 4-4-0 and matching cars that was purchased by Gilbert and was used as the inspiration for its Frontiersman 4-4-0 and matching cars:
http://www.tcawestern.org/alexander.htm
No mention of scale on the TCA caption, and zooming in doesn't produce a sharp image - did Alexander ever dabble in making custom S scale locomotives?
