AND WE BOUGHT IN AT THEIR BOTTOM:

Bobbi Marsh puts her 11-year-old son to bed each night and then heads to her job at General Motors Co. (GM)'s metal-stamping plant in Lordstown, Ohio. She gets home in time to make him breakfast.

Marsh, 34, is one of thousands of auto workers in the U.S. benefiting from the return of a third shift at factories -- often from 11 p.m. to 7 a.m. -- translating to 24-hour-a-day production at many plants for the first time since the industry collapse in 2009. At the nadir, some plants ran only one eight- hour shift.

The new third shifts, adding more than 4,300 jobs in four states at GM alone, bring jobs to the economy and revenue to governments as well as demand at odd hours for everything from daycare and dentistry to financial services and food. U.S. auto plants this year may operate at about 81 percent of capacity after falling as low as 49 percent in 2009, according to estimates from IHS Automotive in Northville, Michigan.

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