Track at the backdrop
Work in progress: This section is still a work in progress — content is being added and revised continuously.
What is checked? Whether a track lies behind a backdrop or so close in front of it that vehicles brush it. “Behind” means: in the corner that the curve of a rounded backdrop corner cuts off the board.
Why does it matter? At a rounded corner the backdrop does not stand on the board edge but a little in front of it. Whatever lies in that corner can neither be seen nor reached once the layout is built. If a track runs too close in front of the backdrop, car bodies and mirrors scrape along it.
How to fix it: Move the track inwards, away from the backdrop. At a rounded corner, a smaller backdrop radius or a square corner also helps.
Numbers & defaults: The minimum distance from the track centre to the backdrop is half the clearance width of NEM 102, 24 mm in H0 (13.5 mm in N). A track in the corner behind the curve is an error, a distance that is too small is a warning. Tracks below the board top do not count.