Class 73 History

The British Rail Class 73 is a dual-mode electro-diesel locomotive built between 1962 and 1967 by English Electric for British Rail’s Southern Region. A total of 49 were produced (later numbered 73001–73049), designed to operate on the 750V DC third-rail network while also using a small onboard diesel engine for unelectrified sections.

In electric mode, they produced around 1,600 hp, but only 600 hp on diesel, making them best suited to mixed traffic, light freight, and engineering work. Their flexibility saw them widely used across the Southern Region, including later duties such as the Gatwick Express.

After privatisation, many remained in service, with major upgrades carried out by GB Railfreight, creating the Class 73/9 variant with a far more powerful diesel engine. Today, they continue to operate in infrastructure and specialist roles, noted for their longevity and versatility.