Train Speed Test
Real-time GPS speed measurement for your train journey.
How the Train Speed Test Works
TrainSpeedTest.net uses your device's GPS receiver via the browser Geolocation API to measure how fast your train is travelling. When you tap "Start Trip," the app begins collecting position samples from GPS satellites. Using the Haversine formula to calculate distance and dividing by elapsed time, it computes your current speed in real time.
The app applies an exponential moving average filter to smooth GPS noise and guards against impossible acceleration values. If your device reports native Doppler speed (many modern phones do), TrainSpeedTest.net will use that for improved accuracy.
Tips for Best Results
- Place your phone near the window for better satellite visibility
- Allow 10–20 seconds after starting for GPS to stabilise
- Speed readings freeze inside tunnels — this is expected
- Results are estimates, not official railway telemetry
See our How It Works and GPS Accuracy pages for the full technical explanation.