Prof. Cholachat Rujikiatkamjorn discusses Geosynthetic Solutions for Soft Subgrade Stability under Cyclic Loading in Railway Applications. As demand for rail infrastructure continues to grow—driven by increasing passenger and freight transport needs—there is an urgent need for more resilient and sustainable track foundations. Heavy haul railways often traverse challenging ground conditions, such as saturated soft estuarine soils, which contribute to frequent track failures and escalating maintenance costs. Recent investigations along the South Coast rail line in New South Wales (Australia) have revealed significant track degradation caused by subgrade mud pumping—a phenomenon requiring immediate attention. This webinar presents comprehensive laboratory studies aimed at understanding the mechanisms behind mud pumping and exploring effective mitigation strategies. Cyclic consolidation sheds light on how saturated soils can fluidize and migrate under intermittent cyclic loading. The research highlights the potential of geosynthetics—including geotextiles and geocomposites—in mitigating mud pumping. Additionally, prefabricated vertical drains (PVDs) demonstrate long-term effectiveness by significantly reducing EPWP through shortened drainage paths. The combined use of PVDs and geocomposites emerges as a promising solution for enhancing track stability under heavy rail loads. Case studies at the towns of Sandgate and Bulli, NSW, demonstrated the effectiveness of relatively short PVDs and geocomposites in enhancing the stability of a track built on soft subgrade.