What is the reason for haywire iPhone scrolling on a French high-speed train? I write this seated on a TGV as it grande vitesses its way across southern Germany from Augsburg to the French border. Last week I was on an identical train travelling in the opposite direction from Paris to Augsburg.
I settled down and plugged in my iPhone, using Apple’s standard European charger and Lightning cable. After a time I noticed that the phone was giving problems. Scrolling was jerky and I got the impression that there was a fault with the touch calibration. I tried to send an email four times and each time it was despatched before I had finished typing, presumably because the send button was activated without deliberate input.
After resetting the phone I tried again. But the problem persisted all the way to the end of the journey in Germany. However, after leaving the train the iPhone was operating normally, completely without scrolling problems. So I assumed this was a temporary glitch and thought no more about it.
This morning, when I boarded the return train I found the same phenomenon. The scrolling went haywire and the phone became almost unusable. Eventually I unplugged the power and was astounded to find the problem cured. So, connecting the power supply to the phone somehow causes this problem. It was quite clear: plug in and scrolling and touch went mad; unplug and all is ok.
What can be the cause if this? I have travelled extensively by train in the UK and never experienced this. Nor does it happen on the Eurostar trains between London and Paris. I can only assume there is some irregularity in the 220v power supply on the French TGV. I intend to check this with Apple and will report back if anything comes of it. Meanwhile, it remains a big mystery.
FURTHER THOUGHTS: On both journeys I was sitting on the upper deck of the train, therefore just a few feet beneath the catenary. However, since the problem manifests itself only when the power cable is connected, the cause is likely to be something to do with the frequency of the AC power supply. There is a difference between the catenary power supply in Germany and France. In Germany, catenary is 15,000 volts with frequency of 16-2/3Hz. In France the supply is 25,000v at 50Hz. The lighting and individual power socket circuits are stepped down to 220v AC at 50Hz. Since the erratic behaviour was noticed only in Germany, there is possibly an explanation lurking here.