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Drax: new biomass wagons

The Challenge – New Biomass Wagon

Drax is a predominately coal fired power station, generating 7-8% of the UK’s electricity. This has turned Drax into one of the world’s largest sustainable generators.

Lloyds were commissioned by Drax to design a new rail wagon, biomass is one third less dense than coal, so one of Lloyds’ objectives was to design a wagon that would be able to optimise and carry as much biomass as possible. The goal was to create an industry leading wagon that even NASA would not be able to improve on. All of this IP and technology is owned by Drax.

Lloyds Register started in 1760 and has expanded internationally, everywhere there is a major port in the world there’s a Lloyds Register office. Drax approached Lloyds for the new biomass wagons after they previously developed a top door system for a retro fit to coal hoppers. There were challenges in finding available space for the additional kit, which led Lloyds to using the space at the ends of the wagons for the outer hoppers.


The Design

The current hopper wagons that were currently used on the railway principally for coal had no top protection however; biomass needs to be kept dry so this addition was an integral attribution to the new wagons. Pneumatic steel aluminium door solutions were created but challenges arose with this process – making it safe in the loading gauge when the wagons are on the mainline railway and making the door opening process automated.

Compared to a normal coal hopper wagon the new biomass wagon is 116 meter cubed, almost a 30% increase in volume from the traditional wagon. Part of the challenge was to try and control the excessive flow of the biomass pellets at the unloading plant. The product control flaps in the lower doors are interesting and have not previously been done before. As soon as the concepts and parallel streams are firmed, other people will start getting involved in the assembly process.


The Build Process

WH Davis was originally formed in 1910 as a repairer and latterly, a manufacturer of wooden bodied coal wagons for the Nottinghamshire coal fields. In just over 100 years there have only been two changes of ownership, and it is now the last independent British manufacturer of rail freight wagons. The manufacturing process begins with creation of small sub-assemblies which are then moved into the main hall where they are married to the main body. This is then placed in a rotator for the final welding to ensure that all welding, where possible, is down hand. When the main body is fully assembled, it is moved to the final fit-out workshop. Here the automatic roof door system is fitted together with the bottom doors, the buffers, the brake work and the drawer gear. All the parts needed to make it a fully operational wagon.

The Drax wagon is effectively a supersized hopper in that the cubic capacity of the hopper is larger than anything that is currently operating on the UK network. The project is also interesting because on the current regulations and limits of loading gage, this cubic capacity cannot be bettered.

The wagons are completely conformant with standards and regulations which has made the project a challenge over the 18 months. Lloyds Register were able to predict changes coming down the track, and so we were able to plan and inform Drax and the approvals team about what would need to be done and how they were going to address those issues.

The design solution that Lloyds Register and WH Davis have come up with is industry leading and fulfils the requirements Drax needed. It delivers a greater quantity of biomass on every train and is a wagon that will not be surpassed for many years.

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