Duncan's arrival to Sodor was in the year of 1958 and made his appearence in the Thomas & Friends Television Episode "Home at Last".
Originally Duncan was bought as a spare engine due to the fact the workload was too much for Sir Handel and Peter Sam to handle with unassisted and after Peter Sam had his accident with the slate cars, he was reguaged to a 2ft 3in. Duncan was brought to Sodor along with the return of Skarloey to help Sir Handel with his work in the quarry. At first Duncan was rude and arrogant and Peter Sam quoted that his violent temper were because he was a factory in Scotland (of which he obviously worked at first) could've been the source. However after his first accident of a following tunnel derailment on a stretch of track south of Cros-ny-Cuirn, he began a rivalry with Rusty due to the fact of him being a Diesel. He then complained about Peter Sam for his funnel, Sir Handel for his wheels and Skarloey for his polished brass. But then Skarloey was so ticked off with Duncan's carelessly procrastinated attitude, that he put some sense into him by telling Rheneas' story of how he single handed ran the railway to show him that special funnels, Wheels and polish were not so important.
Duncan means well but can rock and roll denpending wherever his mood will take him & he still seems to ignore Rusty's warnings. Though he is quite a powerful worker for his size and will be there for a friend in need.
Duncan's first addition to Take-Along the model had white wheels.