Key Takeaway
The train Wi-Fi problem stems from basic physics, particularly the challenges posed by high speeds. Trains traveling at 150mph struggle to maintain stable connections as they switch between mobile towers every 45 to 60 seconds, leading to the Doppler effect. According to Luke Kehoe from Ookla, onboard Wi-Fi performance is poor. Additionally, many train carriages act as Faraday cages, blocking signals due to metallized window coatings. Some operators, like SNCF, are now openly addressing these connectivity issues, acknowledging that Wi-Fi quality may not match that of home networks due to speed and coverage limitations.
The Challenge of Train Wi-Fi
The core issue surrounding train Wi-Fi stems from fundamental physics.
As trains speed through the countryside at 150 mph, their onboard antennas struggle to maintain stable connections while switching between mobile towers every 45 to 60 seconds.
This quick transition leads to what engineers refer to as the Doppler effect—the same phenomenon that causes the pitch of a passing ambulance siren to change.
Luke Kehoe, an industry analyst at the connectivity intelligence firm Ookla, states: “The performance and quality of Wi-Fi onboard European trains is very poor.”
However, the issue extends beyond just speed.
Many train carriages effectively act as Faraday cages, featuring metallized window coatings that block radio signals, similar to how lift doors disrupt mobile calls.
Some train operators, such as the French transport giant SNCF, have begun to address these challenges openly, rather than making unrealistic promises.
“Due to the lack of coverage and our speed, the quality of the Wi-Fi may differ from that in your home,” SNCF acknowledges.
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