Duck is painted dark green. The initials "GWR" are painted on the sides of his pannier tanks in yellow and red. His number (8) is painted on the sides of his cab in yellow, on a rectangular black background with a yellow outline. He has red bufferbeams and a grey running board, valences and wheels.
Duck is the only character in All Engines Go to carry English lettering on his body.
Duck, along with the Slip Coaches, are the final characters from the original series to return in All Engines Go.
Strangely, Duck's Metal Collection release features several discrepencies from his final design. This is unlike other characters such as Salty, whose final releases are changed to more closely reflect their final appearance.