The British Rail Class 90 electric locomotives were built for mixed-traffic duties, operating from 25 kV AC overhead lines and produce 5,000 bhp. They weigh 84.5 tonnes and can typically achieve a top speed of 110 mph.

The Class 90 is a modernised derivative of the preceding Class 87 locomotive, having been originally designated as the Class 87/2. During the 1980s, British Rail Engineering Limited had submitted an offer to build 25 examples to replace various aging electric locomotives, including the Class 81, Class 82, Class 83, Class 84 and Class 85. It was selected over numerous rival proposals, including the InterCity 225 and the Class 89; the type was manufactured by BREL at Crewe Works between 1987 and 1990.

The Class 90 was introduced to service during the closing years of British Rail, being used for both passenger services and freight trains alike. Following the privatisation of British Rail, the type has served with various operators, including Greater Anglia, Virgin Trains and GNER; it was, however, displaced largely from regular passenger services during the 2000s and 2010s. Presently, Class 90 locomotives are usually employed on heavy freight trains and occasional charter services.