Detroit ? About 47,600 hourly workers have decided to leave General Motors Corp. and Delphi Corp. through buyout or early retirement offers, accelerating the distressed companies’ plans to cut costs by paring their work forces.

At GM, where about 35,000 people will depart – mostly through early retirements – Chairman and CEO Rick Wagoner said he was surprised by the numbers. But he said the number of takers will allow the Detroit company to reach its target reduction of 30,000 manufacturing jobs by Jan. 1, two years ahead of schedule.

GM previously announced plans to cut its 113,000-person U.S. hourly work force by 30,000, closing a dozen plants by 2008.

“Over the past several months, we have accomplished a great deal in our strategy to reshape GM into a company that is more nimble, more global and built for long-term success,” Wagoner said Monday.

The deadline for GM workers to file paperwork for the offers was Friday, but they have seven days to change their minds. Friday also was the deadline for workers at Delphi, GM’s former parts operation that is now a separate company, to file for early retirement incentives.

Delphi said Monday that about 12,600 employees represented by the United Auto Workers union took early retirement offers at the Troy-based automotive parts supplier, which filed for bankruptcy protection last October. Some Delphi workers also have an additional buyout offer on the table with deadlines that are more than a month away.