The British Rail Class 99 is a class of dual-mode electro-diesel Co-Co locomotives that will haul freight trains on both electrified and non-electrified lines. It is based on the Stadler Euro Dual platform. Able to reach speeds of up to 75 mph, the powerful machines can run on 25 kV AC electrified lines with a power of 6,000 kW at wheel. In addition, they feature a high-power low-emissions Stage-V engine allowing operations on non-electrified lines.

The locomotives are expected to enter service in 2025 and will most likely be first used for intermodal work on the West Coast and East Coast mainlines. They will be maintained by Stadler at a new facility in Leicester