|First Appearance||Thomas Helps Out (Cameo)|
|Basis||Not any known quarry machine|
|Livery||Orange-red with his name painted on his side of his bonnet in white|
|Voice Actor|| Currently unknown
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. The boulder caused a large deal of havoc along the Narrow Gauge and Standard Gauge lines before destroying the Narrow Gauge sheds.
After this incident, he was severely reprimanded by Sir Topham Hatt, and was going to be sent to the Mainland before Miss Jenny Packard bought him to work with The Pack. Miss Jenny had her workmen repair him to the point where he could work without getting severely out of control, and he worked successfully with the Pack for a long time. Sir Topham Hatt, noticing his improvement, sent him to work with the Narrow Gauge engines at the Blue Mountain Quarry, where he currently resides.
Thumper is very laid-back machine. He is cool and collected, but he can be very accident-prone. He is a friend to just about all the road vehicles, and enjoys chatting with the engines on the railway. He is also a very persistent and hard worker.