RaTraPla

The circle does not add up. One piece too few, one too many — and on the carpet it fits anyway, because every joint can twist a little. That is what RaTraPla calculates. Which is why rings close here that would never close on squared paper. RaTraPla plans layouts for wooden toy railway — not with generic track, but with the pieces that are actually in your box. Please note: the app's screens are in German; a glossary of the labels is at the end. HOW IT WORKS Pick a configuration, start a plan, set the build area if space is tight, tap a piece. Each new piece attaches to the open end of the last one, and the line grows. Dragging moves the whole connected chain; letting go snaps it back into place. Rotate in 45° steps, mirror, duplicate, delete — all in the bar above the pieces. THE PLAY AT THE JOINTS Push two pieces together, hold one, and twist the other gently as far as it goes. The gap that opens on the far side is the play. Measure it once, enter it in millimetres — and RaTraPla knows how far your track can really bend. Because a ring does not close thanks to "a few percent of tolerance". It closes because many joints each twist a little. Tap two open ends: if the play is enough, one button pulls them together. If it is not, the app tells you to the millimetre how much is missing. PEG AND SOCKET Wooden track has a direction: socket at the front, peg at the back. RaTraPla draws both, and never offers you a fit that does not exist in reality. It even knows those puzzling short pieces with two pegs or two sockets — and shows you in a drawing what they are for. YOUR BOX, YOUR MEASUREMENTS Measure your track and enter what you find: lengths, radii, angles, turnouts. Curves and turnouts get a small scale drawing that follows the values as you edit them and shows where to put the ruler. Enter how many of each piece you own, too. The bill of materials then tells you what your plan needs and what is still missing. You may plan beyond your stock — that is what wish lists are for. Three configurations come with the app. The one for IKEA LILLABO was measured on real track; the ones for BRIO and Eichhorn carry the widespread wooden-railway standard and are meant to be checked against your own pieces. Every value is editable, and you can build a system of your own. BUILT FOR SMALL HANDS Open ends catch the finger, so they stay easy to hit even when the plan gets crowded. And under almost every setting there is a sentence saying what it is good for — this app has a very thorough test engineer. YOUR FILES ARE YOURS Everything is stored as readable JSON in your own iCloud Drive folder "TrackPlanner", visible in the Files app — or locally on the device if you are not signed in to iCloud. A plan carries its configuration with it: pass on the plan, and the measurements travel along. No account, no sign-in, no ads, no tracking. The app talks to no server other than your own iCloud, which holds your RaTraPla files. And then the circle adds up after all. Not because the arithmetic works out, but because every joint twists a little — and because you measured, once, how much. RaTraPla was called TrackPlanner until November 2026. The iCloud folder keeps the old name, so existing layouts stay where they are. RaTraPla is an independent project and is not affiliated with BRIO, Eichhorn or IKEA. Those names only say which track fits which. GLOSSARY OF ON-SCREEN LABELS Baufläche = build area Brücke = bridge Enden zusammenführen = join two ends Gerade = straight Gleispläne = track plans Konfigurationen = configurations Kreuzung = crossing Kurve = curve Offene Enden = open ends Rampe = ramp Schienenteil = track piece Spiel an den Stößen = play (mechanical slack) at the joints Stoß = joint between two pieces Stückliste = bill of materials Verzug = how far a joint is pushed out of true, as a side gap in mm Vorrat = stock (pieces owned) Weiche = turnout Wunschzettel = wish list