Re: This smells like BS.
"Literally take the power off - traction, signalling, comms, the lot. See what dies, what doesn't reboot etc. Used to take ages afterwards going round replacing cctv monitors, resetting clocks etc."
Maybe not as bad as the lightning strike that just hit the NE mainline signalling/control centre in York yesterday and took out the entire system, affecting trains and the entire line from London to Edinburgh.