Lots of Diesels from the Other Railway have been seen or mentioned.
These diesels work on the Other Railway and pull goods and frieght. They are friends with D199, D261, The Red Diesel, The Passing Diesel, Old Stuck-Up, and Diesel. They haven't been seen much, but Oliver saw some when escaping from scrap, and a few were seen at the National Railway Museum.
When Thomas called a meeting at the sheds, all the engines recalled times when a diesel from the Other Railway came to Sodor. Percy mentioned the time when Stepney told him about diesels he passed on his journey to Sodor. There numbers were D701 and D782, and there was also an American Diesel, called a 'Western'. Oliver got confused with Percy, and asked if he meant D7101, who was rennamed Bear. Percy corrected him. Oliver also mentioned that when he was hiding from the diesels, he saw two diesels. He said that one of the two diesels looked like Diesel, and the other was numbered D5701, who looked like BoCo.
Some diesels from the works now work on the Other Railway, which means that The Works Diesel is the last one left.
The Yellow Diesels Edit
Two yellow diesels were seen on several occasions.
These diesels are very rude, like most diesels. They both resemble Diesel 10. They, along with the othe diesels from the Other Railway were sent back home after they tried to invade Sodor. They are believed to brothers, and they both think that Diesel 10 is the best diesel locomotive that was ever built.
One of them was seen sticking out of a shed at the Dieselworks in a cancelled episode.
The Green Diesel Edit
A green diesel who resembles BoCo has been seen several times.