3 Steam Engines Gruff is the twenty-second episode of the twentieth series.
It is autumn and Thomas meets Toby along his branch line, who thinks the trees look spooky. Thomas moves along and sees a broken fence. He informs Trevor of the fence, who says he will tell Farmer McColl about it.
That night, Thomas tells the other engines about the fence. Percy is nervous as he sets out to pull the mail train. He is making his deliveries and comes across a bridge on the branch line and all of a sudden, he hears a moaning sound. Frightened, he rushes back to Tidmouth Sheds to tell the others. He runs in so fast that he rockets right into Henry, who rolls further into his berth. Gordon is not amused nor interested. Percy, however, is very apprehensive toward the sound he heard.
The next morning, Percy tells Toby and Thomas about it. Thomas assures him there is probably nothing to worry about. Toby, on the other hand, is baffled and scared by this and is not looking forward to crossing the bridge on the way to the Quarry.
Later, Thomas is nearing the bridge and decelerates, puzzling Annie and Clarabel. Thomas tells them what he is up to, but suddenly hears the moaning sound Percy told him about, hollers and dashes away.
Thomas, Percy and Toby meet up at Ffarquhar and discuss the sound they heard. Percy, remembering the story of The Three Billy Goats Gruff, thinks it is a troll. Toby agrees, reminding the others about how the littlest goat survived by going across the bridge first and telling the troll to eat his bigger brothers. The engines are all very scared and do not want to be consumed by the "troll."
Toby claims first and Percy second, leaving Thomas to go third. At the bridge, Toby, Henrietta and Percy hurry cross, leaving Thomas on the other side. Slowly proceeding across, Thomas, Annie and Clarabel hear the noise and listen more carefully and realise it is a cow mooing. Toby and Percy are surprised too and they fetch Jem Cole, Farmer McColl and Trevor to rescue the cow, who had escaped from the broken fence. Thomas takes her back to Farmer McColl's farm.
That night, Thomas, Percy and Toby tell the other engines about their adventure. Edward, Henry, Gordon and James laugh, but Toby and Percy are agitated and say it is not that funny. Thomas, not having any hard feelings, says it was a little "a-moosing."
- Annie and Clarabel
- The Welsh Bird Watcher
- Jem Cole (Does not speak)
- Farmer McColl (Does not speak)
- Emily (Cameo)
- One of Dowager Hatt's Friends (Cameo)
- The Lady with the Big Hat (Cameo)
- Tidmouth Sheds
- Tidmouth Goods Station
- The Works
- The Watermill
- McColl Farm
- Anopha Quarry (Mentioned)
- John Hasler as Thomas
- Keith Wickham as Edward, Henry, Gordon, James and the Welsh Bird Watcher
- Nigel Pilkington as Percy and Trevor
- Rob Rackstraw as Toby
- Teresa Gallagher as Annie and Clarabel
- Maggie Ollerenshaw as Henrietta
- Going by production order, this is the twelfth episode of the twentieth series.
- This episode is one of seven in the twentieth series produced by Robert Anderson, the rest being produced by Tracy Blagdon, along with Sidney Sings, Letters to Santa, Toby's New Friend, Henry Gets the Express, Henry in the Dark and The Christmas Coffeepot. This episode is among the latter three that have a copyright date of 2016 like all the other episodes in this series, while the former four are dated 2015.
- This episode is based around the fairy tale of The Three Billy Goats Gruff; the story is also mentioned in the episode by Percy and Toby.
- This episode marks a few things for Trevor:
- This episode marks the last time Toby sleeps outside of Tidmouth Sheds.
- This is the first episode that Jem Cole is referred to by name since the seventh series episode The Refreshment Lady's Tea Shop.
- On the Nick Jr. US broadcast of this episode, it was paired with Henry in the Dark.
- Throughout most of the episode, the workmen's shed on the right of Tidmouth Sheds is in the same position as in Henry Gets the Express, Henry in the Dark and The Christmas Coffeepot, but at the end of the episode, it disappears.
- When Percy bumps into Henry at Tidmouth Sheds, Henry is sent backwards. But when Gordon is speaking to Percy, Henry has moved to where he was previously, without any indication he moved.
- The bridge on the Watermill has two lines, but in this episode, there is only one.
- The Dutch dub incorrectly credits Lee Pressman as the episode's writer.
- When Thomas, Percy and Toby are at Ffarquhar Station, the gates at the level crossing are missing.