Dapol HAA and HEA hoppers
BR air braked coal hoppers. Starting with the HAA bulk coal 'merry-go-round' hoppers British Rail adopted the air train brake system for new high capacity wagons. These wagons were also intended to run at higher speeds, reducing rail freight transit time. The HEA design was used for domestic coal distribution, with improved suspension engineering suitable for running at 60mph on Speedlink services with the long wheelbase open wagons and vans.