11.   Traditional toy-train controllers use variations in the power supplied to the track for limited control of a locomotive.

12.   During the outages, controllers used a battery-operated radio to tell incoming planes how to approach, Cassano said.

13.   Flight controllers will use the photographs to determine how they might fix the latches during a future mission.

14.   For instance, controllers now use headsets with only one ear piece instead of two that allowed them to listen simultaneously to pilots and colleagues.

15.   Fremont controllers use the lines to tell controllers in Honolulu, Tokyo and Manila about current air traffic, he said.

16.   It is possible that the forward air controller was using a laser to designate the target, but officials said they believe this was unlikely.

17.   The controllers were using a go-slow strategy, leaving aircraft in take-off position with running engines for up to one hour.

18.   At the heart of the problem are undertrained, overworked and demoralised air-traffic controllers using dangerously obsolete and poorly maintained equipment.