Duke

duke is possably the skarloey railways number 7 and the mid sodor railways number 1 he has mostly been seen in the cameo of nameboards

apperances
rheneas and peter sam (nameboard)

rheneas peter sam and sir handle (nameboard cameo)

skarloeys special train (nameboard cameo)

secret mine (Nameboard cameo)

finding falcon (nameboard cameo)

he may have debuted in the private video