The first diesel is painted green and cream and had a yellow face. It is based on a BR Class 31 Brush Type 2. 31120 is another member of this class. This diesel's number is D701 and its head code is "4F12".
The second diesel is painted maroon and is based on a BR Class 52 "Western". All diesels of this class were given two-word names, the first word being "Western" and thus the type became known as Westerns.
The last diesel is painted dark green all over and is based on a BR Class 40. The Diesel and Old Stuck-Up are also members of this class. This diesel's number is D782.
Class 52's basis
Two of the diesels with Fergus at a Day Out With Thomas event
The first diesel was painted with yellow and black "hazard" stripes and appeared to be based on a Class 08. Unlike most Class 08 featured in the Railway Series and the Television series, his/her face appeared to be descending from his/her cab, rather than his/her front end.
The second diesel was painted in British Railways' "Rail Blue" livery with large yellow warning panels, and appeared to be based on a BR Class 28. BoCo and D5705 are also members of this class. He/she appears to be D5701, since that engine was the only Class 28 to be painted in "Rail Blue" during the class' existence.
Upon closer inspection of the main line going away from the signal box, a third diesel engine can be seen in the background. Its class is unknown.
The fourth diesel was from Barrow-in-Furness. It shouted a warning that Oliver was escaping. When Douglas was helping Oliver, Isabel and Toad escape from scrap, he/she witnessed the event. Douglas told the stowaways to take no notice of the diesel. This diesel was not seen in any illustrations, making it unknown what his/her basis was.
“Visiting diesels sometimes boasted about how special they were. Usually, BoCo and Bear had to spend the next day smoothing ruffled feelings.”
―The Author, Old Stuck-Up, James and the Diesel Engines
Several diesels from the Other Railway have visited the Island of Sodor on several different occasions. Visiting diesels are known to be particularly haughty, as they feel superior to steam engines and often put the steam engines down.
The diesel is painted black and is based on a BR Class 08. Over seventy members of this class survive today in preservation, while around 100 remain in service on the national rail network. They were in fact the most successful shunting engines in the world, with 996 of them built.