Visualize a kilometer-scale subterranean quantum rail hub beneath a future megacity, engineered inside a vast natural basalt cavern. Layer multiple transit decks, maintenance galleries, and service platforms around a luminous central switching ring. Several original streamlined magnetic trains converge from different directions while tiny maintenance crews provide scale. Use a landscape 4:3 dramatic high-angle view, with sweeping rail lines directing the eye toward the hub center and deep cavern openings extending into haze. Combine cool cyan guidance lights with warm amber service bays and subtle volumetric mist. Render wet basalt, brushed metal, ceramic panels, condensation, and coherent infrastructure in cinematic industrial realism. Original technology only; physically understandable rail geometry; no combat, franchise resemblance, text, logos, watermark, floating buildings, or collage artifacts.