Episode 22: Duke's Reunion was uploaded on September 28, 2016 and is the 6th episode of the 3rd season.
Duke remembers his siblings back on the Ffestiniog Railway, and how he did not get a long with them. However, the other engines can see that he really does miss them.
- Welsh Pony
- Peter Sam
- Sir Handel
- Little Giant (appears in flashback)
- Bertram (does not speak)
- Talyllyn & Dolgoch (do not speak)
- Mr. Percival (does not speak)
- Duncan (cameo)
- Den (cameo)
- The Sodor Garratt (cameo)
- Percy (cameo)
- Duck (cameo)
- Stanley (cameo)
- Fred (cameo)
- Luke (cameo)
- Ivo Hugh (cameo)
- Donald (cameo)
- Mountaineer (mentioned)
- Causeway Castle
- Crovan's Gate
- Ffestiniog Railway
- Cas-ny-Hawin (Mid Sodor Railway)
- Transfer Yards
- This episode was inspired by the movies Finding Dory and Home Alone.
- All 9 RWS Skarloey Railway engines appear, though Duncan, Ivo Hugh, and Fred do not speak.
- Bertram was originally going to have a much larger role, but it was too difficult to impersonate EnterprisingEngine93's voice for him.
- This marks the first appearance of SI3D's 2012 Duke model, though the 2006 one is used for shots with the smaller models.
- Duke's voice was changed from T1E2H3's earlier works as the gravelly, gruff American voice was too difficult to do for a whole episode. The character Colonel Hathi from The Jungle Book was the main inspiration for the new voice.
- This episode was delayed because of re-shoots and a busy schedule.
- It would technically be impossible for Duke and his siblings to run on the same track in the present day: the Ffestiniog is 1 ft and 11 & 1/2 inches, while Duke, along with the other Skarloey Railway engines, runs on track that is 2 ft and 3 inches.