That definitely works, but it requires a cable, balancing two devices on a potentially small seatback tray etc. On most trains I've traveled on, Wi-Fi (if avai

That definitely works, but it requires a cable, balancing two devices on a potentially small seatback tray etc. On most trains I've traveled on, Wi-Fi (if available) also works much better since the antenna for that is usually on top of the train, and windows are sometimes coated with a metallic paint to keep out solar radiation.