The Twin Engines is the fifteenth book of the Railway Series.
Sir Topham Hatt has just been having a disturbing time! He ordered one goods engine from Scotland and was surprised to receive two!
They had both lost their numbers and no one knew which was which. So he didn't know which engine to keep.
The engines are getting dragged down by the amount of work they have, and they are pleased to hear a goods engine is arriving from Scotland. However, the Fat Controller is surprised to hear two engines have arrived and goes to meet the engines, but only manages to discover they have "lost their numbers", as they put it, and they have since named themselves Donald and Douglas. The Fat Controller orders for them to have numbers painted on them and puts them to work, but is determined to find out which engine should not be there and send him back.
Donald and Douglas (now #9 and #10 respectively) realise they have only numbers painted on their tenders. One afternoon, Douglas is shunting in the Yard and worries about being sent away, unfortunately forgetting to shunt Thomas' Special Coach. The twins decide to swap tenders so as to convince the Fat Controller that Donald has taken his goods train, but he isn't fooled and reprimands Douglas severely.
The Fat Controller threatens to send one of the twins away and they behave, until a spiteful brakevan delays Douglas' goods train. Donald soon puts the van right, but when Donald crashes into a signalbox and James has to do his goods work the brakevan and the trucks, sensing James' fury, hold back, and Douglas has to help as a "banker". The brakevan holds back again, but gets its comeuppance after Douglas accidentally crushes it. The Fat Controller comes to supervise the clean-up, and has mixed feelings about Douglas staying.
Winter comes early, and Donald and Douglas ask to help clear the line. They manage to rescue Henry from a snowdrift, but they are still worried that they will be sent back. Edward tells Percy that they need a "deputation", and the big engines elect Percy to be their "disputation". Percy tells the Fat Controller that Donald and Douglas will be scrapped if they return to Scotland, but the Fat Controller has already made up his mind: he gives the twins a new coat of paint and allows them to stay.
- Donald and Douglas
- The Spiteful Brakevan
- The Fat Controller
- Annie and Clarabel (do not speak)
- The Foreign Gentlemen (do not speak)
- The Fat Controller's line "Now, which one of you is 57646?" is a subtle joke, as, had the Fat Controller checked the British Railway rolls, he would have realised that the Class 812's only went up to 57645.
- Gordon references "Tugboat Annie", a 1950s Canadian television series about a tough old widow who captained a tugboat.
- David Mitton has said that an adaptation of "The Missing Coach" was half-finished for the second season, but Britt Allcroft scrapped the idea, citing that the plot would be too complicated for young viewers.
- The illustration on the front cover shows one of the twins with British Railways' cycling lion logo.
- The title of "Break Van" is a play on the word brakevan, as in the story, the van breaks.
- When Percy, Gordon, and Henry mix up the pronunciation of "deputation" Edward is visible in the shed; however, he does not correct them. Furthermore, it is mentioned that Percy ran back to the shed quickly, implying that he went immediately back. Edward was previously seen with some coaches, so if he had to take a train or shunt the coaches, then Percy should have arrived at the shed long before he did.
- In the fifth illustration of "Break Van" the Spiteful Brakevan is facing forwards, but in the next illustration, he is facing backwards. Also in this illustration, James' black lining along his wheel arches is gone.