跨铁路人行桥：长跨距与两侧高差

Design a pedestrian bridge crossing a railway corridor, where the span is long and the two sides sit at different levels. Show a slim steel deck crossing four tracks in a single clear span with no intermediate support, its structure a shallow through-truss with a solid parapet to hand height and a tall fine mesh above — the mesh continuing over the top as a partial cage across the railway section only, as safety requires, then opening out again at the approaches. Detail the two ends differently to handle the level difference: on the higher side the deck meets the ground almost directly with a short ramp, while on the lower side it requires a long switchback ramp and a lift tower. Show the electrification masts and overhead lines below with a clear vertical clearance, and the tracks running away in perspective. Detail the deck surface in textured epoxy with a tactile strip, and the parapet mesh as almost transparent so the trains remain visible. Include a train passing beneath and people watching from the bridge. Show clear daylight. Photorealistic, infrastructural, grey steel, three-quarter view.