Rusty's Ghost Engine/Behind the Scenes

Television Series
Rusty's Ghost Engine was a fictional narrow gauge saddletank locomotive created by Britt Allcroft and David Mitton. It shares the same basis as Skarloey, who is based on the Talyllyn Railway No. 1 locomotive, Talyllyn.

In 1998, the engine was introduced in the fifth season of Thomas the Tank Engine & Friends. He appears in the episode, Duncan Gets Spooked with no dialogue and the sixth season music video, Boo! Boo! Choo-Choo via stock-footage.

O gauge model (Small scale)
Skarloey's small scale model was used to represent the Ghost Engine in a brief scene when it fell into the swamps below the ravine at the set of the Old Iron Bridge.

This is one of the few occasions in which the model appeared in Series 5.

O gauge model (Large scale)
Skarloey's large scale model was prominently reused as the Ghost Engine. According to Models on TV, an online magazine, the model used was specially modified so that it could only travel a certain distance before a motor swung it off from the bridge.

In a following scene, the model was also covered in white powder to represent a ghostly apparition.

Firefly formation
In the episode, as Duncan began to see flickering lights that looked like an engine in front of him, it is said fireflies were making a formation of an engine. This was achieved via rotoscoping, as an animated sequence of small golden yellow circles were traced over the footage, frame by frame, to produce realistic action.

While the Ghost Engine shared the same basis of Skarloey, the engine formed by the fireflies resembled Rheneas and Smudger's basis, Dolgoch.