The Case of the Puzzling Parts

"It's a mystery. I love a mystery! Imagine us as special agents!"

- Paxton

The Case of the Puzzling Parts is the twenty-third episode of the twenty-second series.

Plot
Sidney has a flatbed with some parts that are needed, but he forgets why the parts are needed. Paxton decides that he and Sidney should be special agents to find out what they are for, they found out from Thomas that the parts are for a diesel engine. While they are searching for more clues to find, Sidney starts to have a few problems with himself, and Paxton points out that he has a wonky horn, a broken lamp and a faulty buffer, and he is coughing up black smoke. Both diesels realise that the parts are for Sidney himself.

Characters

 * Thomas
 * Whiff
 * Dart
 * Sidney
 * Paxton
 * Skarloey
 * Reg
 * Diesel
 * Scruff
 * Luke
 * Owen

Locations

 * Vicarstown Dieselworks
 * Vicarstown Diesel Sheds
 * Diesel 10's Shed
 * Crocks Scrap Yard
 * Road and Rail Runby and Road Bridge
 * Tower Windmill
 * Whiff's Waste Dump
 * Blue Mountain Quarry

UK

 * John Hasler as Thomas
 * Keith Wickham as Whiff and Skarloey
 * Bob Golding as Sidney
 * Steven Kynman as Paxton and Dart
 * Tim Whitnall as Reg

US and CAN

 * Joseph May as Thomas
 * William Hope as Whiff
 * Bob Golding as Sidney
 * Steven Kynman as Paxton and Dart
 * Keith Wickham as Skarloey
 * Tim Whitnall as Reg

Trivia

 * Going by production order, this is the twenty-fourth episode of the twenty-second series.
 * According to Sam Wilkinson, this episode was originally written for the twenty-first series, but was later moved and reworked into the format of the twenty-second series after the twenty-first series was cut short.
 * Paxton breaks the fourth wall once again in this episode, as does Sidney.
 * This episode marks the last and only of a few things:
 * The last time Skarloey is seen without the brass ring around his funnel.
 * Whiff, Scruff, Dart and Luke's only appearances in the twenty-second series, as well as Sidney and Skarloey's only speaking roles in the twenty-second series.
 * The final appearance of Whiff in the original series.
 * Scruff's last appearance.
 * The last appearance of Whiff's Waste Dump in the original series, although it was mentioned in the next series and will later appear the reboot, and starting in the reboot onwards, Whiff's Waste Dump is mentioned as Whiff's Recycling Plant.
 * On the Nick Jr. US airing of this episode, it was paired with Outback Thomas.

Goofs

 * When Thomas backs away from Sidney, he makes no puffing sounds and Paxton's engine does not make a sound when he reverses alongside Sidney.
 * Sidney and Paxton travel on narrow gauge track in the tunnel at the Blue Mountain Quarry despite being standard gauge engines.
 * Throughout the episode, Sidney's wheels move slower than the speed he is travelling at.
 * Nick Jr.'s captions misspell Sidney as Sydney throughout the episode.

UK/AUS

 * Here Comes the Steam Team!

GER

 * Big World! Big Adventures! - Adventures In Sodor

El Caso de las Piezas Misteriosas Sprawa Tajemniczych Części Загадочное дело