Back on line in 72 hours: To reconnect Mexico City's complex electric grid after last September's earthquake, engineers zeroed in on the most critical repairs, aided by remote operation of substations

For Jorge Gutierrez Vera, last Sept 19 began like most other Thursdays in early autumn. In the cool morning air, he was ready to play a game of tennis at a racquet club in northwest Mexico City before going to his office at the local power authority. Suddenly, with an extended roar like an explosion, the earth pitched and shook violently.