Challenges to national defence in contemporary geopolitical situation

War rarely announces itself politely; instead, it abruptly restructures systems that once appeared routine into matters of existential urgency. Nowhere is this transformation more evident than in Ukraine’s railway network. Since the full-scale invasion of February 24, 2022, Ukrainian Railways (Ukrzaliznytsia) has evolved from a largely invisible economic backbone into a central artery of national survival. This article examines how the railway system absorbed simultaneous shocks, including military attacks, infrastructural collapse, and a minus 44.3% contraction in the transport sector while maintaining operational continuity under extreme wartime pressure. Drawing upon statistical data, policy documents, and theoretical insights from resilience and vulnerability research, the analysis situates railway infrastructure at the intersection of logistics, geopolitics, and humanitarian response. The study argues that Ukraine’s railway system represents not merely a resilient infrastructure but a strategically transformative mechanism that catalyzed a structural shift in international freight flows, enabling rail to partially replace maritime routes that previously dominated export logistics. The article contributes to transport resilience scholarship by illustrating how large-scale conflict accelerates adaptation cycles, strengthens institutional learning, and redefines the operational role of railway systems in contested environments.