Caterpillar, the world’s biggest maker of earth-moving equipment and heavy duty engines, announced on Monday it was rehiring workers for the first time since the economic downturn took hold two years ago, in a tentative sign that the US industrial economy might be recovering.

The manufacturer is widely seen as a bellwether of the US and global industrial economy. In 2007 it was one of the first big US companies to warn that the country was entering a serious economic downturn.