Diesel 40125, nicknamed "Old Stuck-Up" by James, is a haughty Diesel.
BoCo was to show the visiting Diesel around, but when he saw steam engines in the shed he refused to go further and insulted the railway for keeping them in service. A furious James bestowed upon him the nickname "Old Stuck-Up".
The next day, Old Stuck-Up was about to leave when he remembered he needed refueling. He attempted to use BoCo and Bear's part of the shed to be refuelled and cleaned, but slid on cleaning fluid on the rails and crashed into the back of the shed. He was sent home after being talked to severely by the Fat Controller; BoCo noted that while he couldn't hear everything, he didn't think it sounded particularly flattering.
Old Stuck-Up is rude and arrogant like most diesels and believes that steam power is subpar to diesel.
Old Stuck-Up is based on a BR Class 40 1Co-Co1. Another member of this class is The Diesel.
Old Stuck-Up is painted in a British Rail "Rail Blue" livery with yellow warning panels.
- Old Stuck-Up was the first non-human character in the series to be created by Christopher Awdry.
- Unlike most Diesels in the Railway Series, Old Stuck-Up's number wasn't fictional. When the new TOPs numbering system was introduced, all Class 40's were numbered between 40 001 - 40 199. The real 40125 was withdrawn from service and cut up at Swindon Works in May 1981, three years before the setting of "Old Stuck-Up".
|98462 and 87546 • The Workshop Engines • The Foreign Engines • Diesel • The Foreign Engine • The Derailed Engine • Jinty and Pug • The Diesel • The Scrapyard Engines • 199 • Gordon's Brothers • The Passing Diesel • Other Railway Diesels • King James I • Old Stuck-Up • Alfred and Judy • Toby's Brothers • 8783 • The Old Engine • The Highland Engines • The Diesel Shunter • 31120 • 10751 • Wilbert • Sixteen • Sixteen's Friends • Albert • Bahamas • D5705 • Lemberg • Pretty Polly • The Dukedogs • British Railways|
|Lady • Spencer • Hiro • Hiro's Friends • Connor • Caitlin • Stephen's Competitors • The Mainland Engines • Gator|
|Silver Jubilee • Helena|
|Spencer's Special Coaches • Connor's Coaches • Caitlin's Coaches|
|The Flying Thistle • Thirteen • The Fast Mail Train|