Clean Air Power, a UK headquartered clean transport solutions provider, has been working with rail freight operator Freightliner to retrofit a class 66 – the diesel-powered workhorse of the British Rail freight industry. The aim of the project was to find a practical way to refit the class with a hydrogen fuel supply that’s compatible with the EMD diesel power unit. The project has been summed up as a success, so what’s the route now for the ‘66?