Percy the Small Engine is the eleventh book of The Railway Series published in 1956. It is the last book illustrated by C. Reginald Dalby. The four stories are:
- Percy and the Signal: After playing jokes on Gordon and James, Percy decides to stay out of their way for a while, but when he is asked to take a train to Knapford he gets careless and goes over to tell them. Seizing their chance, they warn him about "backing signals", and as he stops for the signal outside Knapford, he is convinced that he is waiting for a "backing signal". He ends up making a fool of himself, and Gordon sees the whole episode.
- Duck Takes Charge: The Fat Controller is getting a new engine to help Percy, but Gordon and James tell Percy that if he worked harder they wouldn't need one. Percy, cross, works all day and is exhausted, but is happy when the new engine, Montague, known as Duck for his "waddle", arrives. They have a happy day together, but then the big engines order them about. Percy and Duck, in retaliation, block the entrance to the sheds. The Fat Controller comes and tells all five engines off. Percy is sent to work at Knapford, and Duck manages the workload alone.
- Percy and Harold: One day at the airfield Percy meets a noisy helicopter, Harold, who says railways are slow and out-of-date. Percy, furious, is later taking some trucks to Knapford when he sees Harold in the air and decides to race him. At the harbour, Percy thinks he's lost, but his fireman sees Harold looking for a place to land. In congratulation, his crew and the workmen sing a song about the race.
- Percy's Promise: Thomas is busy and asks Percy to take the Sunday School children home. Percy agrees, but it starts to rain heavily as it's time to leave. Percy stops in front of a flooded paddock, but can't go back, as a bridge has collapsed. As he crosses the paddock, water sloshes into his fire and he stops. Percy struggles on, fueled by floorboards from the guard's van. After Harold drops some supplies for them, unfortunately landing on Percy's boiler, they make it to safety, and the Fat Controller congratulates the two.
The book contains examples of:
- The Big Race: "Percy and Harold".
- Both Sides Have a Point: Even though Sir Topham Hatt was very angry with the big engines for ordering Duck and Percy around, he was also less than pleased towards Duck and Percy for seeking revenge, despite being pleased with their work.
- Bratty Half-Pint: Percy to the big engines.
- Bullying a Dragon: As the narration puts it, the trucks found out that playing tricks on Duck was a mistake.
- Bully Hunter: Duck and Percy stood up against Gordon, James, and Henry.
- Determinator: Percy in "Percy's Promise".
- Fantastic Racism: Harold states that railways are slow and out of date.
- Gang of Bullies: Gordon, James, and Henry in "Duck Takes Charge".
- Hypocritical Humor: James is dismissive of Percy needing help as a shunter, scoffing that "any engine could do it". This being the same engine that loathed shunting to the point of going on strike. However:
- Hypocrite Has a Point: James was right to tell Percy the yard would be a happier place without his stupidity and with him working hard instead. Also...
- Hypocrite: After bugging Gordon and James, Percy gets mad when they supposedly push him around. He also has a cow when they banter Duck.
- Jerk with a Heart of Gold: Harold in "Percy's Promise". Despite being snobbish about the railways in "Percy and Harold", he came to Percy's aid during the storm.
- Karmic Tricksters: Gordon and James to Percy in "Percy and the Signal".
- Only Known by Their Nickname: Duck's real name is Montague, but he prefers to be referred to as Duck.
- The Prankster: Percy.
- Racing the Train: In "Percy and Harold", this is a variant of Train vs Helicopter.
- "The Reason You Suck" Speech: James gives one to Percy after hearing him talk about the news about The Fat Controller bringing a new engine, Duck, to help with the yard work.James: Rubbish! Any engine could do it! If you worked more and chatted less, this yard would be a sweeter, better, and a happier place!
- Silence, You Fool!: The Fat Controller does this to Gordon, James, and Henry who were wheeshing. Also doubles as a Big "SHUT UP!" moment.
- Time Skip: "Percy and the Signal" took place in 1949 while the other three stories took place in 1955.
- "The Villain Sucks" Song: Percy's fireman sings this song in celebration of Percy's victory against Harold:Said Harold Helicopter to our Percy, "you are slow
Your railway is out of date and not much use, you know"
But Percy with his stone trucks took the trip in record time
Annnnd! We beat the helicopter on our old branch line! - Very Loosely Based on a True Story: "Percy's Promise" is based on a real event where a train was stranded in five feet of water near Hunstanton, Norfolk, and the crew got the train into Hunstanton by using the floorboards of the guard's van.
- What the Hell, Hero?: Despite commending them for their work, The Fat Controller reprimands Percy and Duck for making a disturbance by blocking the turntable to the sheds to keep Gordon, Henry, and James from getting in. The bigger engines laugh, only to stop when The Fat Controller angry turns to them and lividly tells them off too, as they'd caused the disturbance in the first place by ordering Duck and Percy around, which he considers worse due to subverting his authority. He finishes by telling them that Duck is quite right: that this is his railway and he is the one to give orders, not them.
- Whole Episode Flashback: The events of this book is set in 1955 ("Percy and the Signal" took place in 1949).
