Thumper is a quarry machine with two arms and caterpillar treads. He is used for loosening rocks.
Thumper was built by the Sodor Mining Company and brought to the quarry to help clear rock, but his arms accidentally dislodged an enormous boulder which chased Rusty, Skarloey, and Rheneas down the line before nearly crushing Percy and running into the sheds at the mine. He often got out of control on mining sites and is now used for slate mining.
In Sodor Adventures, he's seen as accident-prone, but still means well. Despite this, he can get carried away with his work very easily, which can cause trouble.
Thumper is painted orange-red with his name painted on the sides of his bonnet in white. His roof is painted black.
- Season 4 - Sea Rescue
- Season 5 - Thumper and the Avalanche and Creepy Cutting (cameo)
- Season 6 - Thumper Helps Out