THE RELATIONSHIP between the MBTA and its largest union appears to be undergoing a sea change under Gov. Maura Healey.

Under the administration of former governor Charlie Baker, a Republican, the Carmen’s Union and the MBTA were often at odds. It started in 2015 when Baker used the fallout from snowmaggeddon to push through the Legislature a three-year exemption from the so-called Pacheco Law, which regulates and restricts how state services can be privatized.

The T quickly privatized its cash collection and counting operation and used the threat of more privatization to prod the Carmen’s Union into matching savings that T officials alleged privatization could offer.

For example, the Carmen’s Union accepted a contract that offered no wage increase in fiscal 2017 and a 1.55 percent average increase over the entire four-year contract. Prior to that contract, wage increases had averaged 2.7 percent a year over the previous 15 years.

In return for the wage concessions, the T guaranteed that Carmen’s Union members would continue to operate the T’s core bus and subway system.

When the Carmen’s Union contract was extended another two years in 2021, workers received an annual 2.5 percent wage increase.

Contract negotiations shifted dramatically this year with Healey in office. Privatization has gone missing from the T’s vocabulary. Instead of contract negotiations taking a year or longer, the T and the Carmen’s Union wrapped up talks in less than seven months.

The MBTA board on Thursday unanimously approved a new four-year contract with the Carmen’s Union that offers raises of 7 percent in the first year, 4 percent in the second, 3.5 percent in the third, and 3.5 percent in the fourth. Hourly wages for entry level bus operators jumped from $22.21 to $30.35

With the T desperate for employees, the authority also offered new incentives to keep workers eligible for retirement from retiring as well as longevity bonuses to keep current workers at the T.

Overall, the new contract will cost the T an extra $55.16 million. The Carmen’s Union represents 3,216 workers, or 52.5 percent of the T workforce. The Carmen’s Union contract typically becomes the template for contracts negotiated by the T’s other unions.

“It’s kind of a sea change in terms of the administration really behind the workforce and making the commitments and the investments that are required for a return to a first-class service level,” said MBTA board chair Thomas Glynn.

“The more we work with this administration we see more mutual respect, which builds morale,” said Jim Evers, the president of the Carmen’s Union.

Phillip Eng, the T’s general manager, said the authority has enough money in its budget to cover the extra cost in the first year and should be able to afford it in out years with the help of $20 million Healey set aside specifically set aside for worker salaries in a recent spending bill.