Air braked coal & aggregate hopper wagons. Modernisation started with the HAA bulk coal hoppers and 'merry-go-round' operation between collieries and power stations. British Rail adopted the air train brake system for this new fleet of high capacity wagons in captive service. The HBA design followed, intended to replace the vacuum braked hopper wagons in domestic coal service to coal concentration depots. These new wagons were also intended to run at higher speeds, reducing transit times. Although suitable for 45mph further modernisation of the suspension was needed for future faster freight service, leading to the HEA with suspension suitable for 60mph Speedlink services.
Dapol have now added the 102tonne glw bogie hoppers used by Freightliner for aggregate service, ideal for use with the new class 66 diesels.