Assessing whole-life carbon footprint of under sleeper pad installation for ballasted track

Increasing awareness of the problems posed by anthropogenic climate change in recent decades has led to growing concerns over the level of carbon emissions attributable to travel, transport, and infrastructure development. Although rail is a relatively low-carbon mode, there is also pressure to reduce rail's carbon emissions to help mitigate the extent of climate change. This paper provides a lifecycle analysis study which estimates the effect on carbon emissions of installing under sleeper pads (USPs) during track renewal on two conventional railway lines in the United Kingdom. The aims and scope of the analysis, the lifecycle inventory method, units used, and lifespan of the intervention can all have an important influence on the result. Although the installation of USPs at track renewal could reduce carbon (CO₂) emissions, these are very low compared with the associated financial and economic impacts, and some considerable time would be needed to generate these advantages. However, USPs might make rail travel cheaper, and the increased demand could be an important indirect effect on CO₂ emissions in the transport system due to the shift from other transport modes. The use of nonrecycled rubber can offset the potential environmental benefits from the reduced requirement for track system interventions (maintenance and renewal needs), so the use of recycled carbon-neutral rubber in USP manufacturing should be incentivized.