Tomorrow’s sleeper: new tracks made from old trains

Together with students and researchers from Windesheim University of Applied Sciences, NS is introducing a sleeper made from old train walls and luggage racks. When refurbishing old trains, the sidewalls and luggage racks are removed. Every year, thousands of written-off walls and racks are involved: a total of 200,000 kilos. Until recently, this material was not reusable or recyclable. Together with Windesheim, NS started looking for partners to do something about it.

Ilse van Eekeren, programme manager for circular business at NS: "The only option for these train parts was to dump them. This doesn’t fit in with our vision because we believe that there’s no such thing as waste. That's why NS, together with Windesheim University of Applied Sciences, started looking for a solution to make the material reusable.”

Innovative technology

The train walls and luggage racks are made of composites. This is a strong and light material that consists of various polymers with reinforcing fibres. Windesheim University of Applied Sciences and NS developed an innovative technology to reuse these old train parts. Albert ten Busschen, researcher at Windesheim’s professorship of Polymer Engineering: "By grinding the train parts in mega shredders, small flakes are created that can be reused to make all kinds of things, from cabinets to desks. A bridge has even been built in Dokkum from train sidewalls."

New sleeper

Ten Busschen is referring to the bridge deck of the Dinzer Bridge in Dokkum. But NS had the desire to return old train material to the railway sector itself. Van Eekeren: "In this way, we want to create a demand for the recycled material ourselves and close the cycle." Together with the research group (the professorship) and some students from Zwolle, the idea was born to make sleepers for the tracks. Thom van Riet, mechanical engineering student: "We pour a mixture of resin and composite flakes into a mould and reinforce it with several layers of fibreglass. This creates a sleeper of super-strong material.” His fellow student Yorn Rudde complements him: "This sleeper weighs 123 kilos. That's a lot lighter than the current concrete versions of 283 kg." And Ilse van Eekeren of NS is also positive: "Our sleeper has even more advantages. As a material, polymers are more sound-absorbent than concrete. What's more, when the composite sleeper needs replacing, we make a new one using the same technique. So we can reuse our old train materials indefinitely."

Testing the sleeper

A prototype has now been made to carry out tests at NS Train Modernization in Haarlem. If the prototype works satisfactorily, NS will extend the testing. Van Eekeren: "I think the great thing about this project is that within our own sector we’re turning waste into new railway material and thereby closing the cycle. It was also a pleasure to work with the enthusiastic students and researchers from Windesheim University of Applied Sciences.”

On our way to making trains 100% circular

This innovation contributes to NS' goal of achieving fully circular trains. Van Eekeren: "Our aim is 100% circular trains, but there will always be challenges. For example, reusing the old train floors from the toilets. But 99.9% is also enough te make me happy.''

On polymer research at Windesheim University of Applied Sciences

Universities of applied sciences not only provide education, but also conduct research. This results in practical knowledge which flows right back into education and practice. The research is carried out by professorships, headed by a professor, the chair of a professorship at a university of applied sciences. The professorship of Polymer Engineering was founded in 2008 to conduct research on polymers in the field of hybrid design, circular economy, sustainable production and industrial additive manufacturing (3D metal printing).

In the photo: Mechanical Engineering students Guido de Wit, Thom van Riet and Yorn Rudde, with Ilse van Eekeren of NS.