Derek is a diesel who works on the Brendam Branch Line.


Derek was built between 1962 and 1965. Little is known about his life before he came to Sodor, but he did work on British Railways. Brendam Branch

In 1998, Sir Topham Hatt bought Derek (who wasn't named at the time) so that he could help out on the Brendam Branch despite the fact that he was worried that Derek have teething troubles. This would proved to be true as he started climbing Gordon's hill his wheels spin violently and his engine gave out. BoCo would later arrive with workmen to fix his engine and comfort him.

The news of Derek's breakdown would soon spread across the island and on Thomas' Branch Line, Thomas told Percy about the Diesel's Teething Troubles, but Percy misinterprets it as Tooth Ache and tells this to Bill and Ben when he goes to collect China Clay. This worries the twins as they believe toothache to be a bad condition in diesels before they are ordered to take trucks to the docks. When they arrive, they tell Edward and Duck who laugh and explain about Teething Troubles and the Diesels cooling system.

The following morning, Derek arrived at the China Clay Works and agrees to push the train from behind while Bill and Ben would pull from the front. The journey began smoothly, however when they approach the same hill, Derek overheats and all three engines are forced to stop near the top of the hill. Bill and Ben's Drivers conclude by saying that the twins can finish the journey but pulling Derek too to which the twins agree and arrive at the docks just in time.

That night, Derek was sent to the works and would gang his name while Sir Topham Hatt congratulated Bill and Ben for their work effort.

Later on after he had been fixed at Crovan's Gate Works, Derek was told by Sir Topham Hatt to head to Edward's Branch Line. However halfway in the journey he approaches Gordon's hill but climbs it with ease and soon gets to work.

The engines became very fond of Derek, except Gordon, who although doesn't dislike him, doesn't like how loud and oily he is. One day Gordon shouts at Derek for getting to close to his paint but Henry told Derek to ignore Gordon and comforts Derek by telling him that he also had flaws when he was first built.

Later that same day after Derek had brought some trucks and is waiting for Gordon to pass by with the express at Wellsworth before going home. He meets Edward and Sir Topham Hatt who explains that Gordon will pull a non-stop Express from Knapford to Vicarstown. When Gordon rushes by, Edward realizes that Gordon is missing two coaches, including the brake coach. Derek thinks that he may have forgotten one but Sir Topham Hatt explains sternly by saying that all Express trains must have a brake coach and not having one is against railway regulations. However, before he can continue Edward interrupts and the three of them are shocked to see the last two coaches have somehow detached from Gordon's train, luckily the guard brakes them to a stop at Wellsworth, suggesting the coupling must have broken. As Edward was busy with a stopping train, Sir Topham Hatt asks Derek if he could quickly give them to Gordon, Derek agreed and is quickly coupled up and pushes the coaches. Gordon meanwhile had stopped at Cronk, the passengers are angry at being late and Gordon is just about to go all the way back to retrieve the coaches when Derek bustles in pushing the last two coaches. The coaches are hitched back to Gordon's train, the passengers reboard and Gordon quickly hurries away. That evening, Gordon apologized to Derek for being so rude to him and he accepts Gordon as a new friend but is mainly happy to be part of the North Western Railway.


Derek is a jolly, enthusiastic diesel engine, who was brought in to assist Bill, Ben, and BoCo at the China Clay quarry. Unfortunately, due to his engine and cooling system, he was highly prone to teething troubles, namely overheating and suffering frequent breakdowns, for which he is apologetic for the inconvenience. As a result, he spends many hours a day having his engine tended to. But Derek is a likable engine and even Bill and Ben decided that they liked him due to his friendly nature.

However, after being fixed at Crovan's Gate Works, Derek no longer suffers from teething troubles, although his engine remains very noisy.


Derek is based on a BR Class 17, also known as the Clayton Diesel-electric Type 1. They were built from 1962 to 1965. Ironically, Derek's problems were undoubtedly inspired by those of his basis, as the twin Paxman engines of the real Class 17s were unreliable, being prone to problems with the camshaft, cylinder head, and other areas. Due to these problems, all Class 17s were withdrawn between 1968 and 1971 and with all but one were scrapped by 1978. One Class 17, D8568, is preserved at the Chinnor and Princes Risborough Railway in South Oxfordshire.

TEOS AppearancesEdit

Season 1Edit

Season 2Edit

Season 3Edit

Season 4Edit

T1E2H3's RWSEdit

More Branch Line EnginesEdit

NWR Origins AppearancesEdit

A BR Class 17 using Derek's model can be seen in the episode Great Western End, although it is not intended him.

Voice ActorsEdit

TV Series AppearancesEdit

Derek only appeared in the TV series once on the Season 5 episode "Double Teething Troubles", where he wasn't even named and was only referred to as "the new Diesel", or simply "Diesel". He would later appear in the music video "Trying" in the 2005 special Calling All Engines.


  • Derek was the first non-Awdry standard gauge engine to be introduced into the television series.
  • Derek was originally going to be named "Paxman", but it was changed for fear it would offend the Paxman brand of diesels, or refer to celebrity Jeremy Paxman. However, the 1999 Thomas and Friends Official Website referred to Derek as "Paxman Diesel".
  • Thomas1Edward2Henry3's voice for Derek is an imitation of The Kipper Runs Again's voice of the character.