Sidney is a kind blue BR Class 08 diesel shunter with short term memory loss.
Sidney was a new diesel brought in for shunting work, mostly to fill in for Donald and Douglas. He has worked in various shunting yards, around the Arlesdale Railway, at the Sodor Ironworks, and at Ffarquhar Quarry with the likes of Mavis, Max, and Monty. However, if you asked Sidney if he's worked at these various places, he would never be able to recall due to his increasingly perpetual amnesiac condition.
However, even so, Sidney's absent-mindedness can have serious consequences. The best example of this would be when Sir Frederick Aura had 'Arry and Bert attack and scrap Patriot when the engine had lost his way. Sidney had been in the Smelters when this had occured, and his absent-mindedness made it more difficult for the authorities to find out how and why Patriot had disappeared, as Sidney could've provided valuable evidence as he was a witness.
Sidney was one of the few engines on hand that could rescue the Flying Scotsman when he was trapped by a rockslide. He quickly brought Thumper for the rescue, and after some quick-thinking, Sidney hauled the LNER engine and all his enthusiasts to the congregation, and was hailed as a hero upon his arrival. Of course, he was not quite sure why everyone was cheering for him, but was glad all the same.
Though Sidney is very useful and strong, saving the day at the most unlikely of times, he had to be sent to the Works to be mended and have his wheels replaced and this, unfortunately, took quite a long time. After two years, Sidney would return to service but the Little Western Engines have had to make do with the workload during his absence, and they may have been left with somewhat sour feelings for the kindhearted blue diesel.
Sidney is kind, well-meaning, and very polite, but he can't remember anything, which makes him very difficult to work with. Few engines can hold a conversation with him without becoming frustrated. However, few should doubt him, because Sidney always seems to come out on top in the end.
- Season 1: Sidney, Conspiracy Theory (cameo)
- Season 2: Grim Messengers of Doom (cameo), Serendipity (cameo), Scot-free (cameo), Waterworks (cameo), James Goes on a Trip (cameo), Rock-Star, Munitions, Swan Dive (cameo), Henry and Kurt (cameo), Swashbuckler (cameo), Thomas and the Fortune Teller (cameo)
- Season 3: This Too Shall Pass (flashback; does not speak), Culdee Fell (does not speak), Ice Breaker (cameo)
- Web Clips: Walter Sliggs - Meet the Characters! (does not speak)
He will likely appear in Self-Fulfilling Prophecy.