One morning, Henry wakes up feeling very ill. He complains about it to James, who grumpily shrugs it off as Henry being lazy. The Fat Controller is also unhappy about this, given that this is the latest in a long line of problems with Henry and not even new parts or paint seem to help. He warns Henry that if he does not get better soon, then he will have to be replaced, to the grief of him and his crew.
Later, as Henry prepares to take his first train, the Fat Controller, determined to get to the bottom of Henry's problems, decides to ride along in the cab having changed out of his usual suit into a crewman's uniform. Henry manages to start, but the fireman is not pleased and notes that Henry's firebox is not producing adequate heat. As a result, Henry quickly loses steam, and has to rest in a siding when he reaches Wellsworth Station, leaving Edward to take care of the train. Henry's crew and the Fat Controller continue to investigate what the problem is, and they discover that the coal provided is unsuitable for him, made worse by the low amount they have been receiving lately. While the other engines have big fireboxes, Henry's is too small to make the amount of heat needed for him to run properly. However, if Henry had Welsh coal, he would easily improve. Although the Welsh coal will be expensive, the Fat Controller agrees that Henry deserves a fair chance and sends for James to collect some.
When the coal arrives, the fireman carefully stokes up Henry's fire to give the best possible results. Henry initially has his doubts, but his mood changes as he comes into the platform with more than enough steam. The Fat Controller is happy to see that Henry is feeling well, and warns the driver not to push him. The driver assures the Fat Controller not to worry, as Henry would not need pushing, but would have to be held back. Henry has a pleasant journey with his passenger train and, for the first time, he makes it to the junction before Thomas. When Thomas arrives, Henry calls him "lazybones" before quickly running off, paying Thomas back for insulting him before. Thomas, too surprised to be cross, reacts with disbelief and Annie and Clarabel agree with him.
- Tidmouth Sheds
- The Wide-Arched Bridge
- Stock footage from Edward, Gordon and Henry and Troublesome Trucks and a deleted scene from The Flying Kipper are used.
- A rare picture implies that James may have been intended to play a larger role in this episode; this picture can be found on the back cover to the 1990 release of American VHS James Learns a Lesson and Other Stories, albeit mirrored. Another shows that Henry was to pull the express coaches instead of the old ones.
- The American title is the same one used by Johnny Morris in his audiobook recordings of Henry the Green Engine.
- This was the last episode introduced by Bonnie Langford during her time on Children's ITV. Matthew Kelly took over from 6th December 1984, but he was not too involved in the series, prompting him to only introduce one pairing (Toby and the Stout Gentleman/Thomas in Trouble), and Children's ITV was not shown until January 1985 when Roland Rat took over.
- At the beginning of the episode, the source of James' smoke is visible.
- Because stock footage is used, the Fat Controller is smiling when he tells Henry that he might have to be replaced.
- As Edward backs onto the train, his eyes repeatedly bounce up and down.
- In the close-up of Henry's fireman holding a piece of coal, a piece of blu tack is visible sticking the coal to his hand, and another one is keeping one of his arms attached to his body.
- When Henry's fireman says "Wait and see. We'll have a roaring fire, just when we want it," blu-tack is visible below his right arm. In that same scene, a part of Henry's paintwork is blue (this is because the large scale tender is really Gordon's covered with green vinyl).
- In the last close-up scene of Henry, he is in his new shape, which was a deleted scene for the next episode, The Flying Kipper.
- As Henry leaves Knapford, the truck at the top of the platform changes into a van and steam rises in between his coaches.
- When Henry's train rounds a bend, one side of the coaches is teak livery. In fact, the Old Coaches were painted emerald green with cream windows surrounds, while the other side remained unpainted teak.
- Throughout the episode, Henry's coaches keep changing their places and positions:
- When Henry collects his coaches from Knapford and approaches Wellsworth, the first class coach, the one with the yellow stripe is in the middle of the train. However, when Henry stops next to the platform, the coach is suddenly at the front.
- When Henry starts out of Knapford with his Welsh coal:
- The brake coach is at the front of the train. However, when Henry is out on the main line, the coach is suddenly the rear one. Then, when Henry approaches the bridge, the coach is suddenly facing the other way round for the remainder of the episode. This is to prevent the teak side, the other side of the coach, from appearing on screen.
- The first class coach is at the rear of the train. However, as Henry passes the bus yard and approaches the bridge, the coach is in the middle. Then, when Henry passes under the bridge, the coach is at the front of the train for the remainder of the episode.
- In the restored version, when Henry backs into the siding, his tender hits the station building, a few chuffing sounds are heard even after he stops, and he leaves the siding soon afterward. Also, Edward does not start moving despite his whistle and puffing sound being heard. Then in the next scene, Henry is back to his original position. This is a deleted scene, and as of 2021, this scene has yet to be fixed officially.
- The narrator says that Henry stopped outside Edward's Station, but his train has stopped at the platform.
- When Henry passes the goods yard, blu tack can be seen under a workman's shoes.
- In the final scene, during the close up of Thomas' face, viewers can see behind his eye.