THE MBTA said on Monday that it is increasing its sign-on bonus for new employees and expanding its reach beyond bus operators.

The T said the previous sign-on bonus of $4,500 for bus operators has been increased to $7,500 and expanded to include rail repairers, track laborers, streetcar operators, subway train operators, service technicians, and fuelers.

The T is running short of workers in all of those job categories, which translates into less service and hinders the agency’s ability to make repairs needed to eliminate safety-required slow zones that are currently plaguing more than a quarter of the subway system.

The new bonuses were announced on the same day that the Massachusetts Taxpayers Foundation released an analysis of the challenges the T faces in meeting its hiring goals. The foundation said the T will have difficulty hiring the workers it needs because so many of its existing workers are retiring or leaving the agency for other reasons.