The bombs rocked the London Underground within 50 seconds of each other near the end of rush hour on July 7, 2005, killing dozens of passengers and injuring hundreds more. Investigators sorted through the wreckage for days before determining that three suicide bombers had boarded the subway trains. A fourth bomber destroyed a bus an hour later. It was the worst attack on London since World War II.

But the majority of the Underground, or the Tube, as it’s known locally, was operating again as the next day dawned. “We were very conscious of the fact that getting the system running was the thing that would make the system safest in that, if we didn’t reward people with chaos, they would likely leave us alone,” said Tim O’Toole, the Underground’s managing director and chief executive.

What made that possible, according to O’Toole, was the response from the Underground’s frontline employees.…