3g usb modem stick reception whilst moving real life

Folkestone to Waterloo : I only got usable reception with the Three usb modem stick when the train was stationery in Ashford station and Tunbridge and then as entering the outskirts of london the stick connected whilst moving, I’m guessing on the majority of the journey the train was moving so quickly it couldn’t successfully switch between widely spread/distant mobile masts during the connection process, and therefore failed to connect at all. Result : the Three USB mobile stick was useless for 80% of the journey, one solution was when static in a station to open about 20 tabs with web pages i wanted to read whilst having reception, and then browse them whilst out of signal and moving, though its not what i’d call a fantastic solution.