Exploring the role of an underground logistics system in enhancing Swiss intermodal freight

• A step-wise construction of CST will have a marginal effect on freight mode share, with substantial effects emerging only when the full CST network is operational. • Intermodal Rail volume remains stable and independent, and increasing train frequency improves rail share, regardless of CST’s presence. • Rail terminal capacity is critical, and expanding capacity significantly improves rail’s competitiveness, keeping it viable even in a fully developed CST scenario. • CST’s full network reshapes freight flows and shortens road-leg distances, capturing a large share of shipments and attracting demand that would otherwise have a long road-leg. This research examines the integration of intermodal freight transport within Switzerland’s logistics network, focusing on the role of Cargo Sous Terrain (CST), a proposed innovative underground logistics system. Using the Swiss Transport Outlook 2050 by the Federal Office for Spatial Development (ARE), we developed an agent-based simulation model to analyse a potential future freight demand scenario considering inland, import and export cargo relevant to intermodal transport. The model evaluates the performance and interactions of road, rail, and CST, allowing containers to choose modes, routes, and schedules. This approach enables the investigation of intermodal dynamics, spatial factors, and transhipment processes. The results show that the modal share of intermodal rail remains stable and largely unaffected by CST, with its performance primarily dependent on terminal availability and capacity, maintaining a competitive position even when CST is fully developed. In contrast, the modal share of CST for intermodal transport is determined by network size, with a full CST network leading to significant increases in CST share. This expansion reduces road-leg distances for both rail and CST intermodal operations and promotes more regionalised freight flows, where specific terminals experience increased demand and shorter road legs. Additionally, the study examines the effects of varying costs and tolerance for delays on modal shares. By emphasising the importance of terminal infrastructure, network expansion, and coordinated mechanisms, the findings offer valuable insights into enhancing the efficiency, competitiveness, and sustainability of Switzerland’s intermodal freight system in response to future demand scenarios.