The Joke is on Thomas

"I had a late delivery last month." "Sorry to hear that but I–" "Thomas helped cheer me up." "Yep! All he needed was a laugh to get him back on track. Maybe that's all you need too."

- Percy, Diesel and Thomas The Joke is on Thomas is the twenty-first episode of the first series.

Plot
Thomas and Percy are making faces at Crovans Creek bridge. The two friends soon head to Knapford where they see Carly and Sandy adding final touches to a special boxcar. Thomas thanks Sandy for bringing him the boxcar while suspiciously winking at her. Thomas then asks Percy to couple up to it, he happily agrees, but then Thomas asks him to just uncouple from it. He does so, but is in for a big surprise, as the boxcar is actually a confetti car and confetti spills out everywhere. Percy thinks of this as a great joke, and all the engines have a good laugh. Soon, Gordon pulls up, wondering what the big mess is, as the engines explain it to him Gordon has a good laugh too, and soon Sandy gets to work cleaning up the mess.

As she is cleaning Diesel races past frantically, upset that he has had his second late delivery in the week. He explains to Gordon that a cow on the rails and a broken bridge caused him to be late. Gordon understands and gives Diesel advice to try hard to be on time with his next delivery. Diesel agrees and, determined, races quickly to get to his next job. Thomas and Percy, who want to make Diesel feel better, tell him that a good laugh can always cheer you up. They tell him jokes, make faces at him, they even sing to him, but none of it works. Diesel stubbornly rolls away, and collects his next delivery. Only for Thomas, Percy, Carly and Sandy to find out that instead of taking the delivery boxcar, Diesel is taking the second confetti car. Thomas explains to a confused Percy that he was planning to surprise Kana with the second car. Carly and Sandy explain to the two tank engines that the second confetti car is very different from the first one, and it is called "Jumbo-ka-blam-o", it has much more confetti, and much more will spill out all over the place. A shocked Thomas and Percy quickly couple up to Diesel's correct delivery, and start racing as fast as they can to give it Diesel, leaving Carly and Sandy worried that if Diesel makes fast turns or hits bumpy tracks, the car will pop.

When Thomas and Percy tell Diesel he has the wrong delivery, he instead thinks they are playing another joke on him, so he rushes away, giving the confetti car more chances to pop. Thomas and Percy continue to catch up to him. Diesel arrives at the docks, with Thomas and Percy right behind him, the latter two out of breath. Thomas once again alerts Diesel about the wrong delivery, and this time, the confetti car pops. After the explosion, Diesel decides that the confetti was the best joke ever, and the correct car is delivered.

Characters

 * Thomas
 * Gordon
 * Percy
 * Diesel
 * Carly
 * Sandy
 * Cranky
 * Kana

Locations

 * Crovan's Creek
 * Knapford
 * Crumble Canyon
 * Brendam Docks
 * Sodor Shipping Company

UK

 * Aaron Barashi as Thomas
 * Will Harrison-Wallace as Gordon and Cranky
 * Henri Charles as Percy
 * Henry Harrison as Diesel
 * Eva Mohamed as Carly
 * Holly Dixon as Sandy

US

 * Meesha Contreras as Thomas
 * Neil Crone as Gordon
 * Charlie Zeltzer as Percy
 * Shomoy James Mitchell as Diesel
 * Jenna Warren as Carly
 * Glee Dango as Sandy
 * Cory Doran as Cranky

Song

 * Get on the Laugh Track

Trivia

 * This is the only episode in the first series to be written by Brian Swenlin.

Merchandise

 * Motorized