How fast is this train moving right now? Start the instrument above from your passenger seat for a phone-based estimate. No train number is needed: it measures the device travelling with you, not a train located elsewhere. A fresh location is necessary before the number is useful.
Get a reading from your seat
Select km/h or mph, press Start and allow the browser to use location. Keep the page visible while waiting for an update. A seat with a reasonable view outside may help reception, but there is no need to walk through the train or press the phone against a window. Stay clear of doors and aisles. A covered station is a poor place to judge whether the tool will work later on an open section.
Check that the number belongs to the present moment
The display estimates movement over the ground using the phone’s location observations and filtering. It is not connected to the cab or the onboard passenger information system. Watch several updates during steady travel rather than treating the first number as definitive. After opening a ticket, camera or another app, return to the gauge and check that location updates resume. A retained value is not evidence that the train maintained that speed while the page was hidden.
Expect gaps underground rather than a tunnel speed record
A train can continue moving when your phone no longer has a usable location. In a tunnel, an underground station or a heavily shielded carriage, a frozen or missing reading does not mean the train stopped. Starting outside the tunnel does not guarantee measurements inside it. Keep missing intervals out of any speed comparison and wait for fresh observations after emerging. Do not infer a tunnel maximum from the last number seen before entry.
Read the journey average separately from cruising speed
Station dwell time and slow approaches belong to elapsed journey time. In an illustrative complete record, 48 km counted in 40 minutes gives an average of 72 km/h; the train may cruise faster between stops. With missing observations, the counted distance may be incomplete, so the displayed average has a different limitation. A published service speed, an onboard display and your session average are not interchangeable quantities. Use the statistic that answers your actual question.
Use peaks cautiously on fast services
The maximum is the highest accepted observation in this session, not a verified train record. A sudden isolated spike deserves less confidence than a sustained, plausible sequence. There is no claim here that every phone or carriage supports every high-speed service equally well. Keep the selected unit consistent when comparing screens, and note that displays can update at different times. The train mode does not grant access to railway sensors or certify the measurement.
End the session before it becomes a different journey
Stop when your intended train segment ends if you do not want platform walking or a bus transfer included. Review the summary while safely seated or stopped. Recent summaries are stored in this browser; they are not an operator travel log or a full exportable route. For arrival times, platform changes and disruptions, use the operator’s current information. Your present speed cannot predict remaining stops, signals or the route ahead, so it is not a reliable arrival-time calculator.
| Condition or factor | What it means |
|---|---|
| Open section, repeated fresh readings | Useful for a passenger’s current-speed check. |
| Tunnel or underground station | Treat unavailable observations as gaps, not measured zero. |
| Journey average below cruising speed | Stops and approaches contribute to elapsed time. |
| A train elsewhere or an arrival prediction | Use an operator service, not this phone instrument. |
Technical references: GPS.gov: reception and measurement conditions; W3C: location observations from the device.
Questions about checking train speed
Can I check a train by entering its number?
No. This page measures the movement of your device. It does not search a railway tracking database or identify a service.
Will onboard Wi-Fi make GPS work in a tunnel?
A working internet connection does not guarantee a usable device location or speed. Treat connectivity and location reception as separate checks.
Can I measure a passing train from the platform?
No. A stationary phone does not measure the speed of an external object. This is not a radar or video-analysis tool.
Why does the onboard screen show a different number?
Its measurement source and update timing may differ. Check units and compare only current observations; this page cannot certify which display is correct.
Can I leave the screen locked for the whole trip?
Do not assume continuous browser recording with the screen locked. Keep it visible for a spot check; use a tested recording workflow for a complete journey.