Further investigations revealed that these detached cells exerted some subtle electromagnetic influence on the wired-up part of the circuit, allowing it to perform its task efficiently.
Apple hasn't been as direct about what's going on, but Wired believes there's been a 24-hour hold on phone-based Apple ID password resets while the company marshals its resources and decides how much extra strictness is required.
Because tunnels block a radar signal, trains rely largely on hard-wired equipment like the box beside the track, which helps drivers and dispatchers talk to each other and controls a machinelike traffic signal, giving the drivers basic commands to stop and go.