> Is there a major environmental/health problem with particulate from regular steel-on-steel railways? In tunnels, from "erosion from the wheels and brakes, an

> Is there a major environmental/health problem with particulate from regular steel-on-steel railways? In tunnels, from "erosion from the wheels and brakes, and the rails", yes: https://www.wired.co.uk/article/london-tube-dust https://www.wired.co.uk/article/london-tube-dust