Sometime before the Locomotive War, Derek ran away from Sodor to avoid capture, taking Sindey with him.
Derek and Sidney arrived at the Transfer Yards one day, as help was needed on the railway during all the chaos caused by the assassin. Later that day, Sidney crashed into Donald at Arlesdale, and Derek volunteered to take his train for him. He did, but ended up breaking down halfway to Arlesburgh. Sidney eventually arrived and helped Derek to his destination. Soon after this, Skiff the railboat was stolen by the assassin and the Professor, and Sidney pursued them. Derek assisted Sidney by taking a bullet for him. The two were taken to the Dieselworks for repairs the next morning.
Derek was at Tidmouth Sheds the day Flying Scotsman arrived to comfort them about Thomas' death. Derek remained silent throughout the meeting, trying to hide his sadness. He later tried to hide it by shunting later that day.
Derek will appear in The Road to Sodor.
Derek is very helpful and caring, especially to Sidney. Although he is plauged by the occassional engine troubles, he remains happy and optimistic none-the-less.
- Derek is the first diesel shown that escaped the threat of being a part of the Diesel Army.