Derby Lightweight (Yellow Diamond) 1, 2 & 4-car DMUs

Introduced: 1954
Coupling code: Yellow Diamond
Underframe: 57ft 6in
Engines: AEC 150hp
Transmission: Mechanical

In all 219 Derby Lightweight vehicles were built, sixteen were the Red Triangle Lightweights, two became the Battery Multiple Unit. That meant that there were 201 Yellow Diamond vehicles. They would be based on all regions except the Southern.

Later builds of DMU had a more advanced control system meaning these sets were non-standard and destined for early withdrawal, with the last withdrawn from passenger use in 1969.

Some vehicles saw departmental use, and three cars survived into preservation.