In 2012 Ricardo was asked by Drax Power Station to design a new super-sized freight wagon to transport biomass material along the UK rail network to its facility in North Yorkshire.

Since entering into service in 2014, the wagons have played a central role in transforming the station into one of Europe's largest generators of renewable power.

The design also won the 'Rolling Stock Excellence' category at the UK’s Rail Business Awards.

A unique design with several patented features

Biomass is a biological plant-based material sourced from forestry and agricultural by-products and is imported into the UK from locations as far away as South America.

Unlike coal, though, biomass pellets must be kept dry at all times. This means that the open-top wagons typically used to transport coal on the rail network would be unsuitable for carrying the pellets from the UK's ports to the power station.

An initial solution, also developed by Ricardo, saw a retrofit of protective top doors to an existing fleet of coal wagons. Even this early work had to overcome some design challenges. For example, freight wagons have no electricity supply to open and close the doors. In response, a system was developed using magnets attached to both the wagons and the lineside: as the train approaches the hopper house at the port it passes a magnet that causes the pneumatically operated top doors to open. A similar magnet then closes the doors upon leaving.

A safety feature was added that meant the train driver turned a key to send a pressure signal along the rake that primed the wagons for opening. This ensured the doors could not be activated by other magnetic activity during their transit and risk damaging overhead wires, bridges and tunnels. 

However, Drax Power Station's plans to increase the use of biomass in its operations meant a new, more efficient wagon design would be needed.