Minimum radius
Work in progress: This section is still a work in progress — content is being added and revised continuously.
What is checked? Every curve in your plan is compared against the minimum radius of your train categories (train profile). If a curve falls below it, the plan check reports the tightest radius of the affected curve run.
Why does it matter? Long vehicles have fixed bogie-pivot spacings and close-coupled ends — on radii that are too tight, couplers bind, buffers lock, bogies scrape. Looks suffer too: an express train on first-radius curves resembles a folding ruler. Manufacturers state minimum radii for long cars; 420–500 mm is typical in H0 for 26.4 cm coaches.
How to fix it: Swap the curve run for the next-larger radius family (the plan grows a little), ease the route with flex track — or be honest in the train profile that only shorter stock runs here.
Numbers & defaults: minimum radius per train in the train profile: the manufacturer’s figure if you enter it for the train, otherwise the recommendation from its longest vehicle — in H0 360 mm for vehicles up to 160 mm, 420 mm up to 240 mm, 500 mm above that (other scales converted in proportion). Without your own trains the rule is paused. You set up your trains in the “Operations” tool, which is coming soon.