Thomas & Friends (1984)

S5E25 Rusty & The Boulder

The Fat Controller has inaugurated a new mine, connecting both the narrow and standard gauge railways. To facilitate this, an ancient boulder was relocated, causing Rusty some concern. Eventually, the boulder breaks free and tumbles down the cliff, racing after Rusty! He narrowly avoids disaster by diverting onto a siding, but the boulder keeps rolling fiercely onward. Meanwhile, at the mine, Percy finds himself trapped with the boulder barreling straight towards him, leaving him with no escape!