2 capacitors failed in a router, stranding 100,000 commuters in Australia.
On the morning of 12th of April at 0740, a problem at one of the signal boxes at the New South Wales (NSW) RailCorp's Sydenham Advanced Train Running Information Control System (ATRICS) signal box complex caused the loss of control for points, routes and controlled signals for all areas under the control of the complex.
As a result, for several hours over 100,000 passengers became stranded either on trains or waiting for trains.
At 7:36:52 on the 12th April 2011, one of the network switches that forms part of the ATRICS LAN at Sydenham (Sydhm_sw1) detected that the adjacent switch was no longer communicating. At 7:37:10 the same network switch detected that the new communicating switch had resumed communicating.
This pattern repeated regularly for sw1 and for other switches connected to the network. This pattern indicates that there was not a complete failure but that one of the network switches was cycling from a failed to an operational state.
As a result the Sydenham LAN became caught in a cycle where it was continually trying to reconfigure itself to address the changing state of the network.
Full recovery was only possible by turning the system off and restarting it.