What makes Conway's filing remarkable is that Conway was a general foreman at the Convention Center and a Hamilton loyalist. The question it raises is how the local's 2,800 members will respond in October, when Hamilton faces reelection.
"I think that contract should have been signed," Conway said. "I don't feel I was properly represented in this negotiation."
Hamilton has insisted that he thought he would be able to sign until May 10 - the day an extension to the union's collective-bargaining agreement expired. He signed the agreement May 9. The Teamsters and the Carpenters union were the only two unions - out of six - to fail to sign the agreement by May 5.
Teamsters officials said as much when the union local charged the Convention Center's board and management on May 12 with bargaining in bad faith.
"We're not concerned about the charges," Hamilton said. "Our position all along is that we did sign the agreement in a timely matter."
As Hamilton's ally, Conway helped him win his most recent Local 107 election. These days, Conway said, "I'm not happy with him or his slate."
Conway is not alone. A longtime opponent of Hamilton's has also filed an NLRB charge against him and Local 107.
The union's "fundamental failure to adequately and fairly represent their members has consequently led to a significant loss of jobs," Edwin J. Taylor wrote in the complaint filed May 27.
Although about 160 Teamsters were on a list to work at the Convention Center, only about 10 would work regularly, plus up to about 30 for a big show.
As the top Teamster at the center, Conway worked every day. Taylor, of Maple Shade, worked occasionally.
Taylor, 52, has been part of a slate that ran against Hamilton as a delegate to the national Teamsters' meeting. Taylor said the Convention Center problems will be an election issue.
"I think it will be the central issue," Taylor said.
It may also come up June 21 at a Teamsters rally set for the Holiday Inn Express near Philadelphia International Airport.
The rally is part of a national road show of union officials opposed to national Teamsters leader James Hoffa and his slate, which includes Hamilton. Hoffa faces election in 2016.
"This is a hot-button issue," Taylor said. "Why wouldn't they bring it up?"
Hamilton said that neither Conway nor Taylor was a member in good standing of Local 107. Conway was kicked out several years ago but had still been allowed to work as a Teamster.
And, Hamilton said, although the Convention Center dispute captured headlines, it represents a relatively small amount of work for Local 107.
"I don't think [the dispute] will have any impact whatsoever" on the elections, Hamilton said.
Besides leading Local 107, Hamilton heads the Pennsylvania Conference of Teamsters and Teamsters Joint Council 53, a regional organization.
When the deadline came, Hamilton was away at a Teamsters convention in Las Vegas and another top Local 107 official, Ed Slater, had left on a long-scheduled cruise.
"Someone should have stayed behind" to sign, Conway said.
Whether the blow-up at the Convention Center makes any difference in Hamilton's future, Conway is still upset. According to sources, Hamilton had been well-liked at the Convention Center and the Teamsters did their work efficiently under his direction.
Now some of the Teamsters' work is being handled by another union and some by SMG, the West Conshohocken company that has taken over the Convention Center's management.
"We were offered a 10-year [customer service agreement]," Conway said. "Everything, jurisdictionally, was fine. We even gained a little work."
For Conway, of Northeast Philadelphia, the contract would have meant the continuation of a good job that would have carried him into retirement. The agreement promised a 3 percent raise every year for 10 years.
Popular with the other Teamsters, the agreement included some "give and take," Conway said.
"If we have to give a little, it would have been better for the [convention] business, it would have been better for the building," he said.
"You would have had bigger shows and that would have meant more work."