Roughly 30 percent of autoworkers at a Toyota engine manufacturer in Missouri have signed union cards, United Auto Workers (UAW) announced Wednesday, making the plant the fourth new union drive launched in the last four months.

The factory in Troy, Mo., just outside of St. Louis, follows union drives in recent months at a Volkswagen plant in Tennessee and Mercedes and Hyundai manufacturers in Alabama.

The effort comes after the union made big gains for members following a six-week strike of three major automakers — Ford, General Motors and Stellantis — last fall. The UAW has committed to unionizing factories across the country, expanding from its power base in the Midwest.