Duck and the Diesel Engine is the thirteenth book of the Railway Series.
We have had two visitors to our railway. One of these, City of Truro, is a very famous engine. We were sorry when we had to say goodbye to him.
City of Truro, the first engine to go more than 100 miles an hour, visits Sodor and has a lengthy conversation with Duck till late at night. Gordon is jealous of City of Truro's record, claiming that he is a domeless engine and not to be trusted. Gordon later tries to equal the record, but his dome becomes loose from the speed and is blown off at the viaduct. That night someone jokes about the event - Gordon believes it's Duck.
The engines are tired of Duck's talk about his Great Western heritage and are happy when a visitor comes. The visitor, a diesel named Diesel, claims he is "revolutionary", but Duck is unimpressed and tells him to shunt some trucks. Diesel attempts to take some rusty old vans away afterwards, but their brakes are on and all Diesel does is derail them. As he cleans up, the trucks start singing a rude parody of "Pop goes the Weasel", called Pop Goes the Diesel.
Diesel believes that Duck made him look silly and plans to have Duck sent away by telling the trucks rude jokes about the big engines and attributing them to Duck. The trucks tell the engines, and when they find out they refuse Duck entry into the shed. The Fat Controller comes to stop the noise, and, after hearing all three sides of the story, kindly asks Duck to go to Wellsworth for a while.
Edward feels sorry for Duck and helps him settle into life at Wellsworth. Duck takes up a position as a banker, but one day a train breaks away and chases him down the hill. Duck manages to slow down gradually, slowing the trucks down too in the process, but they are diverted onto a siding stopping outside a barber's shop. Duck crashes into the wall, and the furious barber lathers his face over. When the workmen come to pull Duck away the Fat Controller points out that if Duck hadn't done anything someone could have been badly hurt. The barber, repentant, rinses Duck's face. To add to his joy, the Fat Controller tells Duck that Diesel has been sent away and he is welcome back.
- To date, "A Close Shave" and Little Old Twins are tied with having the most illustrations for a Railway Series story; nine.
- In the first illustration, a man with a bowtie and a man who looks like a vicar can be seen looking at Duck. Brian Sibley, the writer of The Thomas the Tank Engine Man, jokes the vicar may have been the Reverend W. Awdry showing C. Reginald Dalby what Duck really looks like.
- In the second illustration of "Dirty Work," one of the trucks has the word "Leeds" written on its side.
- "Galloping Sausage" was a nickname given to Nigel Gresley's prototype LNER Class W1.
- In the seventh illustration of "Domeless Engines" Gordon's paint turns lighter.
- In the fifth illustration of "Dirty Work" the panels on Duck's front and the hole where Duck's siderods connect with his wheels are missing.
- Duck's face in "Pop Goes the Diesel" gets smaller at one point.
- Duck and Diesel's faces change colour.
- In the third illustration of "Dirty Work", the first of Henry's stripes is yellow instead of red.
- Throughout this book, The Twin Engines and Branch Line Engines, most of the engines appear to have white buffers.
- In the final illustration of "A Close Shave", Thomas' number is just below his cab and Toby's eyes are missing their pupils.
- In "Domeless Engines", it is said that City of Truro's record breaking run was from Plymouth to Bristol, but City of Truro was actually going from Plymouth to London on the run.