British Rail Class 45 "Peak"

The BR Class 45 Peak was a series of 127 1Co-Co1 diesel-electric locomotives built by British Railways Derby Works between 1960 and 1962, using an uprated Sulzer 12LDA28-B engine producing 2,500 bhp — the definitive and most numerous version of the Peak family that had begun with the ten Class 44s. The Class 45 shared the 1Co-Co1 wheel arrangement and general layout of the Class 44 but benefited from the more powerful Sulzer engine and detail improvements that gave it better performance on the demanding Midland Main Line climbs over the Peak District and the other principal routes assigned to the class across the LMR network.

The Class 45 became one of BR's most widely-deployed Type 4 diesel classes, working not only the principal Midland Main Line expresses for which the class had been designed but also cross-country services across the LMR and eventually on other regions as the BR network was reorganised. The locomotives were reliable and economical by the standards of the early BR diesel fleet, giving BR good value over a service life of up to 25 years on some examples, and they accumulated a considerable following among railway enthusiasts attracted by the sonorous Sulzer engine note and the elegant 1Co-Co1 profile.

Ten examples are preserved, making the Class 45 well represented in the heritage fleet and giving the Peak family a substantial presence on heritage railways.