Clearance overlap
Work in progress: This section is still a work in progress — content is being added and revised continuously.
What is checked? Around every track the Trackplanner lays the envelope your vehicles sweep — automatically widened in curves (car ends swing out on the outside, car centres pull in on the inside; both grow with car length and shrinking radius). Where the envelopes of two unconnected tracks overlap, you get a finding plus a red conflict zone in the plan.
Why does it matter? The classic among expensive building mistakes: on the straight the parallel spacing fits, in the curve passing trains sideswipe. Invisible on paper, discovered on the layout at the first meet — when the tracks are already ballasted.
How to fix it: Increase the track spacing in the curve (parallel tool), use larger radii, or shorter vehicles in the train profile. The clearance overlay (Display → “Clearance”) shows the bands live while you plan.
Numbers & defaults: vehicle width per NEM 102 (H0: 48 mm, editable); curve widening from the car length in your train profile.