Gourdon is a long, fast engine with a streamlined look which tends to make him somewhat high-strung and pompous, built by Sir Topham Hatt I. He acts like a bully towards the other engines. He is an express passenger engine, and works on the main line. When he arrived, he was a vain, very rude bully, but he broke down in a tunnel bridge, and Thomas helped to push him from the tunnel bridge.

Gourdon is based on a cross between GNR A1 Pacific and GNR C1 Atlantic. He has a 4-6-2 wheel arrangement, tapered, Grelsey A3-style boiler and smokebox with neck holders, Ivatt C1-style running plate and cab, Grelsey B17-style drive wheels, cylinders, valve gear and footplate steps, and Holden B12-style dome and tender.