British Rail Class 99 (locomotive)

The British Rail Class 99 was a proposed class of electric locomotives intended for use on Channel Tunnel services in the United Kingdom. Conceived in the late 1980s and early 1990s, the Class 99 was designed to operate on both the UK's 25 kV AC overhead electrification system and the Channel Tunnel's 25 kV AC system, as well as the 750 V DC third rail system prevalent in the southern parts of the UK.

The locomotives were envisioned as versatile units capable of hauling freight and passenger trains, thereby reducing the need for locomotive changes at the Channel Tunnel terminal. The design specifications aimed for compatibility with existing UK rolling stock and signalling systems.

However, the Class 99 project was ultimately cancelled before any locomotives were built. Several factors contributed to its cancellation, including changing operational requirements, budgetary constraints, and the development of alternative strategies for cross-channel rail transport. The focus shifted towards using existing locomotive classes and developing multi-voltage locomotives that could operate under different electrification systems, such as the Class 92.

While the Class 99 never materialized, its conceptual design played a role in shaping future locomotive developments in the UK, particularly in addressing the challenges of operating across diverse electrification systems and facilitating international rail transport. Information about the class primarily exists in historical railway publications, design documents, and project reports related to the Channel Tunnel Rail Link development.