- “Silly blue engine! You're not number one, we're number one!"
"Yeah and there's two of us; so that makes you... number three!”
Mucking About is the fourteenth episode of the twentieth series.
One day, the Pack is working near Thomas' branch line. However, Max and Monty continuously mess around instead of working. They drive recklessly on the road next to the tracks and even cross the tracks in front of Thomas. Edward advises Thomas to ignore them completely.
When Max and Monty return to the dig site, Monty runs over a rock, where one of his tyres launches it at Oliver. This damages his arm, preventing him from working anymore. Thomas has to take Oliver to be repaired and is even more annoyed with Max and Monty as a result. They are taking some construction waste to the dump when they decide to save time by dumping it over the edge of a bridge, unaware that they are right above Thomas' branch line.
Later that day, Thomas is taking a repaired Oliver back to the dig site, but his track is blocked by a large pile of construction waste which has been built up from several of Max and Monty's loads. Thomas hits the pile and derails. That night, Oliver is digging up the pile of rubble while Judy and Jerome put Thomas back on the rails as Sir Topham Hatt watches. In the midst of all of this, Max and Monty dump another load into the pile. They are confronted by a policeman, who orders them to take all of the rubble to the waste dump before the morning.
Late into the night, Thomas is returning home when Max and Monty apologise to him. Thomas accepts their apology but insists that he will not be racing them again. As he leaves, Max and Monty decide to race to the dump with their last load, making dirt fly into Jack and Alfie's faces, much to their annoyance.
- Judy and Jerome
- Max and Monty
- Sir Topham Hatt
- The Ffarquhar Policeman
- Ryan (cameo)
- Rocky (cameo)
- The Foreman (cameo)
- Road and Rail Runby and Road Bridge
- Rail Under Road Bridge and Signalbox
- Thomas' Branch Line
- Whiff's Waste Dump (mentioned)
- Joseph May as Thomas
- William Hope as Edward
- Teresa Gallagher as Judy
- Tim Whitnall as Jerome and Oliver the Excavator
- David Menkin as Jack
- Nathan Clarke as Alfie
- Kerry Shale as Max
- Rob Rackstraw as Monty
- Keith Wickham as Sir Topham Hatt and the Policeman
- Going by production order, this is the twenty-second episode of the twentieth series.
- This episode marks the first of two things for Max and Monty:
- This episode marks the Sodor Construction Company's only appearance in the twentieth series.
- This episode marks the last of a few things:
- The US dub credits "Jam Filled" for producing the episode, while the UK dub credits Arc Productions.
- When the full movie of Journey Beyond Sodor aired on PBS Kids on 17th November, this episode was included after the movie, making it the only episode to not be paired with another episode. This is also the last episode to air on PBS Kids in the US.
- On the Season 20 (Digital Download), the episode is paired with Bradford the Brake Van, while on Nick Jr., it is paired with Very Important Sheep.
- Max and Monty's theme in this episode is similar to the song All Right Now by Free.
- William Hope and Joseph May are credited in the UK credits despite none of their characters speaking in that dub.
- Throughout the episode:
- Max and Monty's eyebrows phase into their heads several times.
- Max's wheels can be seen moving backwards when he is actually driving forwards.
- Both Max and Monty's steering and wheel speeds are out of sync with their movements.
- In the US dub, when Max and Monty dump their loads over the bridge the second time, they swap voices.
- The sound of Monty's wheel hitting the rock is heard before he actually hits it.
- When Max and Monty dump their first loads on the rails, they both have the exact same tree branch in their trays.
- Thomas' side rods are duplicated when he crashes into the pile of dirt and tree branches. The duplicated side rod is moving, contrary to the non-moving wheels and the audible braking sounds.
- As Max and Monty left with their last load of dirt, they have swapped their horn sounds.