A simple GPS speedometer for the view from your train window.
Take it with you
In Safari, tap Share → Add to Home Screen, then choose Open as Web App if shown. Open it once online and wait for “Ready offline”.
No signal? No invented speed.
GPS can fade in tunnels or inside a carriage. Readings older than 10 seconds are hidden. A location fix may be available without a speed reading—try sitting near a window.
Private by design
No accounts, analytics, maps or location uploads. Only your unit preference and the app files are stored. iOS may pause GPS when you lock your phone or switch apps, and can remove offline storage.
For interest only—not a safety or navigation instrument. GPS accuracy is position accuracy, not a guarantee of speed accuracy.