Sleepers, the pieces that lie between tracks to attenuate noise and absorb vibrations, are most durable if they are made of recycled plastic or sulphur concrete. ProRail commissioned a study by the National Institute for Public Health and the Environment (RIVM) to establish this.
The rail manager is looking for alternatives to the current cement concrete sleepers in order to reduce CO2 emissions. Sulphur concrete is concrete based on sulphur and not cement.
RIVM investigated other types: copper-treated wood, untreated wood, plastic reinforced with steel and plastic reinforced with glass fibre (composite). It also investigated whether there are contaminants in the components and to what extent they are released.
It is not yet known whether ProRail will use the other sleepers. “We are going to look further into that and also into financing,” says a spokesman. “The entire track will have to be taken out again, of course, which will all cause inconvenience and it will also have to meet all the safety requirements and be sustainable