Mashantucket - Engineering department employees at Foxwoods Resort Casino voted Thursday to join Local 30 of the International Union of Operating Engineers — as they had months ago.

Only this time the rules were different.

Thursday's vote was 139 to 103, with the union needing a simple majority of those casting ballots to prevail.

Back in May, employees who voted 128 to 123 in favor of affiliation were thwarted by the Mashantucket Pequot Tribe's labor law, which then required a majority of those eligible to vote to favor union affiliation. At the time, 263 employees were eligible, meaning the union needed support from at least 132 of them.

In June, the tribe amended its labor law to allow union elections to be determined by a majority of those who cast ballots, the same standard employed by the National Labor Relations Board.

"The majority has spoken - again," Gary Archer, the union's lead organizer, said Thursday night. "We're proud to represent the Foxwoods engineers. The tribe changed their law because of the outcome last time, so now we've prevailed."

Neither Foxwoods nor the tribe, which owns the casino, would comment on Thursday's secret-ballot election, which was conducted by the Mashantucket Employment Rights Office. Voting took place in a room near the Great Cedar Hotel's front desk and concluded at 7 p.m. Those eligible to vote included carpenters, carpet and tile installers, electricians, HVAC technicians, locksmiths, painters, plumbers and upholsterers.

The tribe, which contends that as a sovereign nation it is not subject to the National Labor Relations Act, has urged unions intent on organizing Foxwoods employees to proceed under tribal law instead. Tribal law differs from federal law in prohibiting strikes by employees and lockouts by the employer, and also provides for binding arbitration to settle disputes.

The tribe is contesting the outcome of a July 31 election in which bartenders and other beverage workers voted to affiliate with Local 371 of the United Food and Commercial Workers Union. The tribe alleges that election, conducted by the NLRB, was tainted by union organizers and employees who "made inflammatory appeals to voters' political, racial and/or ethnic prejudices."

Foxwoods' table-games dealers voted to affiliate with the United Auto Workers in a 2007 election conducted by the NLRB. Subsequently, the union and the tribe negotiated a contract under tribal law.

In a 2009 election conducted under tribal law, members of the Mashantucket Pequot Fire Department voted to affiliate with the Uniformed Professional Fire Fighters Association of Connecticut. The parties have been negotiating a contract.

The engineers' union first attempted to organize Foxwoods employees in May 2008. In an election conducted by the NLRB, workers rejected the union, 215 to 67.