Overview

The British Rail Class 24 refers to a group of Type 2 diesel-electric locomotives introduced in the late 1950s to replace steam on secondary passenger and freight services. These engines were part of a broader modernisation effort and became a familiar sight on regional routes. They are often discussed in the context of mid-century British dieselisation and railway rationalisation; see more on the class designation Class 24 and the Type 2 category Type 2.

Design and characteristics

Class 24 locomotives were designed as medium-powered, mixed-traffic units. Their layout and equipment reflected the transition from steam-era practice toward standardised diesel-electric machinery. Typical features included a central cab, side bonnets housing the prime mover and auxiliaries, and a four-axle configuration that balanced traction and route availability. For contemporary context, their introduction began in 1958 and continued through 1961.

Production and development

A total of 151 Class 24 locomotives were built by British Railways workshops at Derby, Crewe and Darlington, reflecting in-house construction capacity of the era; these works are noted in period records Derby, Crewe and Darlington. The initial orders were part of the wider 1955 Modernisation Plan that guided diesel and electric replacement of steam; the first tranche of twenty units was directly linked to that programme 1955 plan. The mechanical layout and operational experience with Class 24s informed the design improvements that produced the more powerful Class 25 Class 25.

Service and operations

During their working lives the Class 24s performed a mix of passenger and freight duties, often on secondary main lines and branch services where heavier Type 4 and Type 5 locomotives were unnecessary. They were valued for versatility rather than high-speed performance and were allocated to a number of depots across the network.

Withdrawal and legacy

Withdrawals of Class 24s began as newer locomotive types and changes in traffic patterns reduced the need for older Type 2 machines. The final mainline survivor, number 24081, was recorded as withdrawn from Crewe depot in 1980. Their operational record and role as the basis for subsequent classes make them an important link in the story of Britain’s diesel transition.

Notable points

  • Built as part of post‑war modernisation and early diesel standardisation.
  • Helped establish lessons that shaped later classes and maintenance practices.
  • Often covered in heritage literature and enthusiast studies for their representative role in the diesel era.