Ricardo was asked by Drax Power 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 award-winning wagons have played a central role in transforming the station into one of Europe's largest generators of renewable power.

Originally built as a coal fired power station - Drax now utilises biomass fuel to achieve carbon emissions reductions of over 90%.

A unique wagon 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, biomass pellets must always be kept dry. This means that the open-top wagons typically used to transport coal on the rail network are 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 existing stock to add protective top doors. Even this early work had to overcome some design challenges. For example, freight wagons have no electricity supply to open and close the doors so a system of magnets to trigger and pneumatically operated top doors was proposed. Safety interlocks were included to ensure the doors could not be activated by other magnetic activity during their transit.

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

The UK's largest volume freight wagons

As biomass is less dense than coal, each wagon must carry more load for biomass to remain an economically viable option.

This required a design capable of carrying larger volumes of material yet remaining within the limits of the UK’s loading gauge and operating in compliance with industry regulations.