A New Methodology for Optimising Railway Line Capacity: Improving Infrastructure for Sustainable Transport

The sufficient capacity of railway lines is a key prerequisite for stable and sustainable transport, not only on main or high-speed lines, but also on lines of regional importance that complement the network. Their indispensable role is manifested not only daily, but especially in the event of incidents on the backbone network. One of the main characteristics of these support lines is that they are largely single-track. Another important characteristic is that they alternate between sections with different traffic loads, which significantly changes the capacity requirements along the whole line. Existing modernisation approaches are frequently implemented in a non-differentiated manner, thereby lacking segment-specific prioritisation. The present paper introduces a novel methodology for systematic identification and the ranking of line sections for capacity upgrades. The approach is comprised of three distinct steps: first, the line is segmented using traffic homogeneity criteria; second, limiting journey times are determined through analytical capacity calculations based on the ninth decile of train volumes; and third, infrastructure measures are identified when the actual journey times exceed these thresholds. Potential interventions encompass the introduction of additional block sections, the implementation of passing loops, or the introduction of double-tracking. The methodology was applied to the Havlíčkův Brod–Jihlava–Znojmo line, thereby demonstrating its ability to detect bottlenecks and propose targeted measures. The findings indicate that there is considerable potential for enhancing capacity while concomitantly improving operational safety and cost efficiency. Consequently, this will serve to reinforce the role of diversionary lines within the broader context of the rail network. The proposed framework provides infrastructure managers with a generalisable tool with which to prioritise investments and support the long-term development of resilient and sustainable railway systems.