The race engineer in your sim cockpit.
Two purpose-built tools, one app. Build a race setup from scratch with the Setup Developer, then fine-tune it lap by lap — and even mid-race — with the Setup Engineer. Runs as a transparent overlay on top of your sim. No alt-tabbing. No spreadsheets. No downloading someone else's setup and hoping for the best.
Setup Developer Module
Build your own baseline setup, one question at a time.
Pick your car type and track. Answer simple questions about how the car feels in each setup area — springs, dampers, aero, brakes, differential. onRails offers valid changes at every step and builds a complete starting setup tailored to your car and your driving style. By the time you're done, you know why every value is what it is.
Step-by-step guided build across all major setup subjects
Six car types: Sports, Touring, Open-Wheel, Stock Car, Sprint Car, Kart
Road courses and ovals, with track-trait flags (banking, bumps, chicanes)
Built-in lap logger with graph, best/average/delta stats
Pause and resume mid-session — progress is always saved
Move on straight to the Setup Engineer to fine-tune for more speed
Setup Engineer Module
Fine-tune your setup until it's both comfortable and fast.
You're in the ballpark but something's off. The car pushes through the apex, snaps loose on exit, won't reach top speed on the back straight. The Setup Engineer takes your driver feedback and turns it into specific, actionable changes — lap by lap, corner by corner.
Lap Wizard — Log your lap time, describe the car's overall behavior, set severity, snap your tire temps with a hotkey. Get a ranked list of setup recommendations with clear explanations. Confirm a change, log the next stint, watch your times drop.
Corner Wizard — When one specific corner is killing you. Pick the direction, the phase (entry, apex, exit), what's happening, and how badly. Get targeted advice that won't unsettle the rest of your lap.
In-Race Engineer — A keyboard-only race assistant that takes up minimal screen space. One hotkey to toggle, numpad keys to answer 2–4 quick questions while you're driving. Get a one-line pit-call recommendation you can act on between laps.
simReader Integration
onRails auto-detects your simulator and reads telemetry directly from shared memory. Hotkeys to snap tire temps and last lap/sector times. They appear in app instantly.
Supported simReader sims: Assetto Corsa · Assetto Corsa Competizione · Automobilista 2 · iRacing · Le Mans Ultimate · Project Cars 2​ · rFactor 2
Any and all other sims still supported via manual entry of tire and lap data.
Note: this product is not made by, or affiliated with, developers of the supported games (unless expressly stated otherwise).
Built for Your Cockpit
Choose Windowed mode or Transparent overlay — sits on top of your sim, no second monitor required
Drag any panel to where you want it; position is saved for next time
Customizable hotkeys — keyboard and wheel/controller buttons
Four F1-inspired accent themes: Ferrari red, Aston Martin green, Stake F1 electric green, McLaren orange
Four languages: English, Español, Português (Brasil), Italiano — auto-detected on first launch
Multi-monitor support — jump to any display with one click
Adjustable font size
Built-in spotlight tutorials for every panel
Built for sim racers, by a sim racer.
