STERLING HEIGHTS, Mich. -

The sound of production gave way to a huge celebration Friday afternoon at Chrysler's Sterling Heights Assembly Plant.

It took a lot of believing and hard work to give a doomed factory a new future. Chrysler repurchased the plant out of bankruptcy, invested nearly $1 billion and doubled the workforce to 2,800.

"We're here today because so many of you believed that the only difference between the possible and impossible is that the impossible has never been done before," said Chrysler Chair and CEO Sergio Marchionne.

Workers at the plant are building the 2015 Chrysler 200. Sterling Heights Mayor Richard Notte may be cheering the loudest. Just more than four years ago he joined a protest outside the plant, which is one of many tactics to save it. He said it would have been devastating had it failed.

"This location, 16 (Mile Road) and Van Dyke would have been a ghost town, a blight," he said.

Sterling Heights native John Pyper moved to Ohio to work for Chrysler. When bankruptcy closed that plant, he came home.

"Bright future here. A brand new facility, brand new vehicle," said Pyper.

United Auto Workers President Bob King said success will continue only if labor and management continue a true partnership.

"I'm never gonna pick up the contract and say we don't have to do or we don't have to do that. If Chrysler's got a problem, we're gonna partner with Chrysler to solve that problem," said King.