Double Teething Troubles

"Toothache? He's got teething troubles. That means he's new and is causing some problems. In his case it's in his cooling system."

- Duck explaining teething troubles to the twins

Double Teething Troubles is the twelfth episode of the fifth season.

Plot
Bill and Ben argue over who has rights to some trucks nearby, and, despite BoCo's warnings, derail each other at the points. The Fat Controller decides to send a Diesel to help them, but the Diesel, Derek, is new and has problems with his cooling system, as seen after he breaks down on Gordon's Hill. The news soon spreads, and Percy, who misunderstands Thomas when he mentions Derek has teething troubles, tells the horrified twins the Diesel has a toothache. The next day, Derek arrives and helps the twins with a long train of China clay trucks. However, Derek's engine overheats, and he stops. Bill and Ben pull him and the trucks and Derek is sent to the works. Bill and Ben apologize to BoCo for being rude and they and Duck talk about teething troubles all night long.

Characters

 * Thomas
 * Percy
 * Duck
 * Bill and Ben
 * BoCo
 * Sir Topham Hatt
 * Derek (not named)

Locations

 * Brendam
 * Anopha Quarry
 * Gordon's Hill

Trivia

 * Stock footage from Cranky Bugs is used.
 * Teething troubles usually occur while steam engines, Diesels, and other machinery are operating for the first time after being constructed or restored to working order.
 * In the American narration, the lines "his wheels spun and then there was trouble", "And then it happened", and "...or I shall send you to your sheds" are absent.
 * A rare picture from The Ultimate Diesel Guide shows Derek smiling after he overheats.
 * In Norway this episode is called "Bill and Ben are Restless". The Italian title is "A Diesel Newbie". The German title is "Teething". In Japan, this episode is called "Let's Get Along". The Spanish title is called "Problems of Coexistence".
 * When BoCo tells Bill and Ben to stop fighting, he says "Stop bickering you two" in the UK version but in the US version he says "Stop quarreling you two".
 * In the US version, the line "Next morning, as the twins were preparing to take a long train of trucks away, they heard an unfamiliar whistle" is changed to "Next morning, the twins heard an unfamiliar whistle".
 * S. C. Ruffey's face appears on a truck. It is unknown if this was simply a mistake on the part of the model makers, or if it was an intentional appeaence of the charater.
 * This is BoCo's last speaking role to date.

Goofs

 * It is said that Bill and Ben heard an unfamiliar whistle (Derek's), but Diesels have horns.
 * A grey cord can be seen in Bill's cab when he's in the shed at the end.
 * In the first close-up of BoCo, his front wheels are derailed.
 * During the first night scene in the shed, a grey cord can be seen stretching along Bill's side.
 * A brakevan should have been added to Bill, Ben, and Derek's train.
 * When Percy leaves Thomas, Thomas' eyes are wonky.

Quotes

 * Bill: "That's my line of trucks!"
 * Ben: "It's not. It's mine! Yours is over there!"
 * Bill: "'Smine."
 * Ben: "'Snot."
 * Bill: "'Smine!"
 * Ben: "'Snot!"
 * BoCo: "Stop bickering you two or the only thing you'll have left to share is..." (Bill and Ben race towards the trucks but crash into each other at the points) "...trouble."
 * Bill: "Silly!"
 * Ben: "Silly yourself!"


 * Percy: "Hey you two! This new diesel's got toothache. Good luck!"
 * Bill: "Why does Percy want to wish us good luck?"
 * Ben: "Because he'll know we'll need it, a Diesel with a toothache must be the worst diesel of all!"
 * Derek: "I'm overheating again!"
 * Bill: "Oh pah!"