A Republican plan to stabilize the financially struggling U.S. Postal Service by dropping Saturday letter delivery, phasing out door-to-door service and removing no-layoff clauses from future union contracts was headed for passage by a key House committee Wednesday.

The agency lost close to $16 billion in the previous fiscal year as mail volume continued its steady plummet. Postal Service officials defaulted on two $5.5 billion payments to set aside health care for future retirees, another financial burden causing huge losses. By law, it cannot raise prices faster than the rate of inflation. Legal restrictions also keep it from easily expanding into new products or services.

Republicans have made a priority of phasing out door-to-door delivery in favor of clustered boxes on street corners. The change could save $4 billion annually by 2022.