Thumper

"It's called Thumper. Apparently, it helps collect the rock faster."

- Edward, "Rusty and the Boulder", fifth season

Thumper is a quarry machine with two arms and catepillar treads designed for loosening rocks.

Bio
Thumper was 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. Nowadays, Thumper is used for slate mining.

Persona
Although Thumper had no lines in his appearance, he has been said to act as a "cool man".

Appearances
Thumper only appeared in the fifth season episode "Rusty and the Boulder" with no dialogue.

Livery
Thumper is painted red with his name painted on his side of his bonnet in white.

Basis
Thumper is not based upon any known quarry machine - at any rate, a machine of his type would be extremely hazardous to those around - such as the lack of windows at the front of the cab, making the operator unable to see.