Study on lightning-attraction characteristics of high-speed maglev trains and implications for railway lightning protection

Purpose To support the operational safety and lightning protection design of high-speed maglev railways, this paper quantitatively evaluates how suspension height and operating speed influence lightning susceptibility. It characterizes trends of the critical background electric field with respect to these two variables, tracks the evolution of surface hotspot distributions and identifies dominant attachment locations and their sensitivity. Design/methodology/approach A coupled procedure of “electrostatic field–aerodynamic flow field–scaled assessment” is proposed. The electrostatic model provides surface field-enhancement factors and their spatial distribution, while turbulent-flow simulations characterize near-wall density variations induced by speed. Under a unified leader height, a critical criterion based on a density-scaled breakdown field maps these two fields to a train-wise critical background electric field. Representative regions (nose, roof and bottom or tail) are used to build statistical metrics for hotspot migration and dominance with speed. Findings Increasing suspension height weakens electric-field coupling to ground, raises the critical background-field threshold and reduces the relative contribution of bottom and edge regions. At the same suspension height, a rigidly grounded train has a lower critical threshold than an electrically floating one. Within 0–500 km/h, the train-wise threshold decreases slowly with speed. Region-wise, roof-tail and bottom-mid sections show a decreasing trend with speed, while the nose stagnation point increases slightly; over the entire speed range, the dominant region remains the roof-tail section. Originality/value Within a unified framework, suspension height and operating speed affect lightning attraction through two distinct channels. Suspension height mainly modifies the threshold and hotspot distribution by changing geometric polarization, whereas speed alters discharge-initiation difficulty through aerodynamically induced density variations. The framework evaluates these effects separately and in combination, explaining the slow variation of the global threshold and the subtle evolution of hotspot locations and providing a physics-based reference for lightning protection design and operational safety assessment of high-speed maglev railway systems.