class-15

The BR Class 15 was a series of 44 Bo-Bo diesel-electric locomotives built by Clayton Equipment and fitted with Brush electrical equipment between 1957 and 1961 for mixed-traffic working on the Eastern Region — a class that became notorious for chronic unreliability and early withdrawal, making it one of the most conspicuous failures of BR's Modernisation Plan locomotive procurement. The Class 15 used a Paxman 16YHXL diesel engine, which in service proved far less reliable than anticipated, requiring frequent attention and causing numerous failures in traffic that disrupted Eastern Region freight and passenger workings.

The Class 15's poor reliability was part of a broader pattern of failures in the BR Modernisation Plan era, when BR had ordered numerous diesel types from multiple manufacturers simultaneously without adequate prototype evaluation — the so-called 'pilot scheme' locomotives were built in numbers before reliability had been properly established, resulting in several classes being withdrawn far earlier than intended after proving unsuitable for the demanding conditions of main-line railway operation. The Class 15 was among the first to be withdrawn wholesale, with the entire class gone by 1971 after just ten years of service for the newest examples.

One example survives in the form of a generator car conversion: D8233 was converted to an electro-diesel generator car and in this form is technically preserved, though it does not represent the Class 15 in its original locomotive form.