Duncan is the number six of the Skarloey Railway.
Duncan is the number six of the skarloey railway and has a tendency to "rock and roll". Upon hearing that the transfer yards were close due to the fat controller's and Mr. Percival's feud he was quite shocked. When the NWR engines migrated to the Skarloey railway they had their new whereabouts found out by D199, following that 10 had presented Lady's corpse which had enraged Duke. The next night Duke had been kidnapped and Duncan was the first to find Duke's tender derailed with blue writing scrawled out by Mr M saying "Move On". He then informed Pill.