Our BSc student Joanne Ax finished her work titled "Assessing the modelled effect of greenery on Dutch railyards, A case study on the Physiological Equivalent Temperature (PET) in the surrounding urban environment". In this thesis, she modeled different types of green infrastructure being added to a typical Dutch railyard and compared the temperature reduction impacts.
The most striking finding to me was the low level of impact beyond the railyards, as the impact was negligible beyond 50 meters, while the whole railyard area, based on Hengelo as a typical standard sized railyard, is 25900 square meters, and a typical railyard zone has large surface area where vegetation could potentially be added (see figure below). There is still a high potential for improvement in future studies that include vertical vegetation, which was not taken into account in this preliminary study. As railyards often have fences and building structures, this could be included, as well as potential green roofs.
You can read the abstract below and the full thesis through the repository.
"Abstract
Climate change is intensifying urban heat in the Netherlands, where railyards form significant heat stress hotspots within densely populated urban areas. However, targeted research on rail infrastructure remains limited. This research aims to assess the effect of greenery on outdoor thermal comfort, expressed as Physiological Equivalent Temperature (PET). A scenario-based microclimate modelling approach was applied for the railyard of Hengelo, which was selected as a case study through a multi-criteria decision analysis (MCDA). Four scenarios were compared: baseline (S0), grass and semi-pavement (S1), shrubs added (S2) and trees added (S3). Under baseline conditions, the railyard exhibits average PET values of 49°C, classified as extreme heat stress. Results show that S1 and S2 reduce the average PET by 0.1-0.5°C, while S3 achieves reductions of 0.9-3.5°C in average PET. The cooling effect is strongly localised and becomes negligible beyond 50 metres from the intervention zone.
These findings partially confirm the hypothesis. The results indicate that shade is the dominant cooling mechanism. It identifies tree-based interventions as the most impactful, providing the biggest decrease in PET. Grass and shrub-based interventions reduce the frequency of extreme hotspots of PET, despite their limited impact on the mean PET. The results demonstrate that targeted tree planting can meaningfully contribute to climate-adaptive design in rail infrastructure."
