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.
Going by production order, this is the twenty-fourth episode of the twenty-second series.
This is both Paxton and Sidney's final episode with a leading role.
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.[1]
If that still happened, it would have been Whiff, Scruff and Merrick's only appearances in the twenty-first series.
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, Luke and Merrick's only appearances in the twenty-second series, as well as Sidney and Skarloey's only speaking roles in the twenty-second series, as well as Whiff and Scruff's only appearances in the Big World! Big Adventures! era.
Paxton and Sidney's last episode with leading roles.
The last appearance of Whiff's Waste Dump in the original series, although it was mentioned in the next series, and starting in the reboot onwards, Whiff's Waste Dump is mentioned as Whiff's Recycling Plant.
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.
In the US dub, Sidney uses the UK term “rubbish” when he says “That clue was a lot of rubbish”, rather than the US term “garbage.”
Sidney and Paxton travel on narrow gauge track in the tunnel at the Blue Mountain Quarry behind the scene in Merrick despite being standard gauge engines.
Nick Jr.'s captions misspell Sidney as Sydney throughout the episode.
