Thomas and Friends - Blue Mountain Mystery - The Movie Special edition

Feature-length animation following Thomas and his friends on the Island of Sodor. Thomas's assistance is required at Blue Mountain Quarry when the narrow gauge locomotives run into a spot of bother. While working, Thomas finds a small green train called Luke hiding out within the tunnels.

It appears Luke ran away because he was responsible for a terrible accident but before Diesel banishes him from the island as punishment, Thomas tries to prove that he is innocent.