Amid lengthening lines of business travelers carrying briefcases and wheeling suitcases in 30th Street Station's concourse last week, two tanned, middle-aged men, dressed like it was a lazy Saturday, boarded a train from a virtually empty platform.

Their only luggage was beach gear, which they easily found space to stow on the overhead racks.

Finding a seat on the 6:31 a.m. NJ Transit train to Atlantic City was no challenge. There were 110 seats per car on the four-car train to the Jersey Shore resort city, and virtually all were empty.

NJ Transit plans to shut down the line, served by 16 cars and four locomotives from Sept. 5 to early 2019 as part of a race against time to install positive train control (PTC), a critical safety system, by the end of the year.

The suspension has infuriated riders, workers, and politicians, who question the need to shut down the line. Train commuters, many of them casino workers, will have to rely on buses that could double their travel time, and train crews that have worked the line for years will likely be reassigned to routes far from home. Local NBC weatherman "Nor'Easter" Nick Pittman started a petition that has surpassed 2,600 signatures urging NJ Transit to reduce Atlantic City line service rather than end it completely.

"What we're concerned about is after that four- or five-month suspension — or whatever it is — the line not coming back," Pittman said. "I'd say I expect it to come back, but I wouldn't be surprised at all if they decided to just pull the plug."

Kevin Corbett, NJ Transit's chief executive, has called the suspension temporary, and money is included in the 2019 budget for the Atlantic City Line. Meanwhile, officials with the Federal Railroad Administration (FRA) have said NJ Transit is under enormous pressure to install PTC. Missing the federally imposed deadline could mean disastrous penalties.

"There are serious consequences to NJ Transit if we do not complete this federally mandated project," Corbett said in a statement last week, "such as FRA fines or a shutdown, or we run the risk of not being allowed to operate on Amtrak's Northeast Corridor."

PTC is 58 percent installed, the agency reported, but federal officials have said it will be a struggle to finish the job before the end of the year.

>>READ MORE: After Philly crash, railroads got more time to install a key safety system. Three years later, some still lag behind

By the end of a typical workday, fewer than 2,000 people will take a trip on the route, less than 1 percent of NJ Transit's total rail ridership, which includes serving nearly 100,000 people out of Newark or New York City's Penn Station.

The beachgoers, Richard Sibley, 58, and Michael Wiskowski, 55, of Bridesburg, take the train twice a month for $10.75 each way. They would likely keep taking beach trips after Labor Day, they said, but the shutdown might make that too inconvenient.

"I'm more inclined to go by the train than by the bus," Wiskowski said. "The train is so much quicker."

The train made a long arc through Northeast Philadelphia to its next stop, Pennsauken, where Eileen O'Brien, 79, boarded. She goes to Atlantic City to spend $60 a day on penny slots with a devotion others apply to morning runs or calls to prayer.

"I don't go down to collect seashells, for God's sake," the New Jersey native said.

Tyrone Comegys, 62, got on with her. The two filled two rows, with O'Brien laughing and chatting over the seat back as rain streaked the windows behind them.

"I enjoy it," Comegys said of the ride he's been taking for 25 years to work at casinos in Atlantic City, most recently in the mail room at Caesars Atlantic City Hotel & Casino. "One of the reasons why is the community on the train itself."

They're both skeptical of NJ Transit's reasons for shutdown.

"If I thought for one minute it was a safety issue," O'Brien said, "I would say, go ahead."

That concern was echoed by passengers and labor leaders who are wary of NJ Transit's commitment to the line, which costs $23.5 million a year to operate. Only 17 percent of that is covered by fare revenue.

Corbett's recent statements highlighted the scheduling disruption PTC installation has caused. Years of minimal hiring has led to a net loss of 50 engineers over eight years, he said, exacerbating the problem. An internal email from an NJ Transit executive stated that equipment from the line would be reassigned elsewhere. The 27 people who work the Atlantic City Line trains will be as well, NJ Transit has said.

>> READ MORE: Atlantic City-Philadelphia rail line to shut down in September

The decision could mean hours of commuting for conductors and engineers, said Steve Burkert, general chairman for United Transportation Union Local 60, which represents NJ Transit conductors. It also could create scheduling chaos. Atlantic City Line conductors tend to be veterans, he said, and seniority rules would give them bumping rights for any scheduling changes, which could displace North Jersey train workers from their routines.

"I'd love to be able to talk some options for [NJ Transit] to see if we wouldn't have to be able to shut down the entire line." Burkert said.

Critics see South Jersey riders and workers suffering to bolster service in the busier northern part of the state.

"We pay the same tax dollars here in South Jersey," O'Brien said.

Politicians have taken up the cause as well, with State Sen. Chris Brown (R., Atlantic) saying NJ Transit should keep morning and evening service running.

"Completely shutting down the Atlantic City Rail Line so that NJ Transit can transfer rail resources to other parts of the state at the expense of our local families is completely unacceptable," he wrote in a statement last week.

The train wasn't as empty after reaching Hammonton. People in casino worker uniforms filed onto cars, which buzzed with easy camaraderie.

"Bring back the train!" one woman shouted to a conductor. "We need it!"

The shutdown means more uncertainty for casino workers. Dolores Mammoccio of Monroe, a 25-year veteran of the industry, lost her job in 2016 when the Taj Mahal closed. Its successor, the Hard Rock Hotel & Casino, made her perform a song to showcase her personality before hiring her back as a porter, she said. Mammoccio did a few verses from Herman's Hermits "I'm Into Something Good" on the train to demonstrate how she won her job back.

Now, she'll have to travel to Avondale to catch the bus to Atlantic City and hope to get to work on time. During the suspension, NJ Transit will offer discounted rides on the Route 554 bus, a local, and the 551, an express route.

"It's going to be a huge inconvenience," she said. "A lot of people depend on this train."

Rail between Philadelphia and Atlantic City made the Shore town a vacation destination in the 19th century, but the line was considered underused in 2011, when service shrank from a train an hour to 12 trains per day out of Philadelphia.

"This is what you would do to a train line if you wanted to kill it on purpose," said Joseph Russell, a NJ Transit activist.

Ridership on the route dwindled along with the casino industry. Current ridership is almost half what it was just four years ago.

Nearly an hour and a half after leaving Philadelphia, the gamblers, workers, and sun worshipers disembarked and entered the 30-year-old Atlantic City Train Terminal. From rafters high in the station, banners promoting the rail service announce, "We've Got a Good Thing Going!"