DARIEN — A contract for town hall employees including raises and capping their final pension benefits was passed unanimously and quickly by the town’s Representative Town Meeting on Tuesday.

The four-year contract with the United Public Service Employees Union representing 30 workers was approved by a vote of 55-0, and offers a retroactive raise for 2014-2015 of 1.75 percent, and 2.5-percent raises for 2016, 2017, and 2018.

Like contracts approved last year for four Board of Education unions, the four-year contract will put union members on a high deductible insurance plans starting next year, but does not require them to make higher premium contributions for coverage.

For the next year, members can remain covered by their current insurance plans at a higher cost before the higher deductible plan becomes the only town-offered plan in July 2016, Town Administrator Karl Kilduff said.

The high deductible plan has a $2,000 deductible for a single person and a $4,000 deductible for families.

The town’s success in negotiating a cap on pension benefits is an incremental move toward what many town legislators feel is a financially necessary move toward getting town workers into defined contribution retirement plans such as 401-Ks, RTM Finance Committee vice chairman Jack Davis said.

The committee voted 8-0 to recommend the wider RTM approve the contract.

Under the contract, retiring workers will be limited to receiving a pension of 70 percent of their final salary in retirement, officials said.

“Anyone who is a good fiscal conservative knows that defined benefit pensions are not sustainable for municipalities or the state,” Davis said.

The contract also includes a provision allowing the town to reopen the contract to revisit health insurance costs in early 2017 after town officials are able to project the impact of the Affordable Care Act’s scheduled 40-percent excise tax on higher cost plans set to go into effect in 2018.

The tax is often referred to as the “Cadillac” health care tax because it targets health care costs above a certain limit under insurance plans for workers that provide generous benefits, Town Administrator Karl Kilduff said.

Kilduff said federal uncertainty over whether the 2018 tax will stay in place, be eliminated, or amended made it impossible to anticipate how and whether it would impact the health plans of town workers.

“Whatever is decided will be a combination of what’s appropriate to being a good employer and what’s appropriate for the taxpayers,” Kilduff said. “There is a lot of talk about whether it will happen or not so it is very much unsettled at this point. We’re assuming there will be something.”

The contract also eliminates so-called automatic longevity bonuses for workers at five-year intervals after their 10th anniversary on the job, officials said.

The percent increase for the wage increases in cost will be 3.4 percent in 2015-2016, and 3.2 percent and 3 percent in the following two fiscal years, according to officials.

Jim Cameron, a delegate in the RTM’s Fourth District, said the wage increases are justified given the high quality and amount of work and assistance town hall employees provide to residents.

“I get to interface with these folks on a daily basis,” Cameron said. “... I think we have a great staff in town hall who provide an incredible level of service. They know how tightly we control the budget and how reluctant we are to add to head count so I think they do a great job and serve the public well. I’ll vote very enthusiastically to give them this pay increase.”