Hamptons Party Starts While the Train Is on the Tracks IN the steamy depths of Pennsylvania Station, just before 5 p.m. on a summer Friday, dozens of people stand with their chins tilted skyward. Sweat drips down the backs of shirts in as many versions of blue check as there are varieties of snowflakes, women in nautically striped outfits fan themselves with fashion magazines, and palm-size dogs pant from within pastel-printed satchels. Clustered together, they stare up at the Long Island Rail Road departures board, stock still as if congealed by the heat. Long Island Rail Road COST $18.25 off-peak; $25 peak for one-way tickets bought in advance. Tickets bought on the train cost more. SCHEDULED TRAVEL TIME About 3 hours 15 minutes from Pennsylvania Station to Montauk, the end of the line. SCENE There will be alcohol. Wear boat shoes, and bring cocktail mixers. ADVANTAGES There is no traffic, cellphone use is allowed, and it is relatively affordable. DISADVANTAGES Boarding is like traveling on the Lexington Avenue subway at rush hour, seats can be few and far between, and the hard-partying crowd turns the train into a rolling bar. Suddenly, the panels of the board flutter. The 5:09 train to Montauk, N.Y., has arrived on Track 18. The Hamptons-bound horde surges forward as one, bottlenecking in the stairwell to the platform like shoppers at the mall on Black Friday, each shoving toward the train that will take him or her "out east," as many Manhattanites refer to the resort towns at the tip of Long Island. This scene is repeated weekly, with 8,000 to 12,000 people heading east on the Montauk Branch each summer Friday, according to the railroad. The cohort seems to be divided into two camps. For some, the Pamplonaesque boarding process, the train's sluggish pace (three hours to Montauk, about the same as a car at a good clip) and its chilly air create a grin-and-bear-it experience. But for many young people off to spend the weekend by the beach, the train is not just a way to get to the party - it is the party. It is more than that, even: another Hampton of sorts, clattering down the tracks. "It definitely starts on the train," said Wynn Mazey, 25, who works in commercial real estate and was on the 9:45 a.m. train on a Saturday in June. The railroad does not keep Saturday ridership figures. It begins at Penn Station. You grab a little breakfast, and then you start boozing. Around him, young men and women sipped from beer cans in paper bags. An empty Champagne bottle rolled back and forth on the floor, as if pitched on a ship's deck. "I don't want to get out there completely sober and everybody is already crunked up at the pool," Mr. Mazey added. "We're already two bottles in," Mollie Moran, 25, said about 10:35 a.m. Empty bottles of sparkling wine shared a seat with her and her roommate Lauren Stallworth, 25. "It makes it feel more like vacay," Ms. Moran added. Across the aisle sat a friend, his arm around a blender for frozen drinks. They were all bound for the Amagansett house they share in the summer with 30 other people, some of whom camp in the yard. "Liquid diet on the train," Ms. Moran said, raising a glass. "And pretty much the whole weekend," Ms. Stallworth added. There was a time when taking the train was a glamorous summer ritual. Jay Gatsby's guests took it to get to his mansion in the fictional West Egg. And there are still hints of the golden age of travel, with passengers dressed in summer whites, clutching wide sun hats lest they be crushed in a weekend bag, and making Champagne toasts - albeit in Dixie cups - to something as ordinary as summer. But mostly, these trips unfold with vignettes of discomfort. The train is less expensive than other means of transport to the Hamptons, but the inconveniences may outweigh the savings. On a recent Friday, Brendan Johnson, 30, en route to Southampton with his wife, Elizabeth, also 30, was crammed into his seat, his knees wrapped around a giant golf bag stuffed with 14 clubs, some wearing little hats with pompoms. In another car, a woman sat cross-legged on the floor, tapping away at her laptop in a doorway; farther down, a woman in a flowered dress was perched on a luggage cubby. Alexandra Catania, 18, who arrived from California with her family earlier that day, stood in a foyer for nearly the entire trip, clutching her little dog, Coco. On a Saturday morning, in a noisy foyer near a pungent bathroom, Patrick Collins, 52, played his Yamaha acoustic guitar on his way to Montauk, as he does every weekend. He said no one had ever spoken to him on the train. "They're already engaged in their cellphones," he said. They're already overconnected. Some riders carve islands of civility amid the packs of partyers. On the Friday train that carried the Johnsons, Hunter Brooks and Nevin Shetty, both 28, sat with a wooden chessboard balanced between them on their knees. Do you have to party on a train? Mr. Brooks said. It's nice to have a conversation. That was definitely a minority opinion. "We're going there to have a good time," Conor Tennyson, 21, said. People probably do feel some sort of way about us - us being, maybe, hooligans. Mr. Tennyson and a dozen friends were headed to the Boardy Barn in Hampton Bays, where customers earn a smiley-face sticker for each drink bought. Riders on the train back to the city are often covered with them. "I've had nights where the train was the best part," he said. Then there was Shane Sabert, 22, who seemed to be everywhere, roving from car to car, but always standing. He was looking for the holy grail of Long Island Rail Road accommodations for himself and his girlfriend: two seats together. "I'm trying to scope out seats for when people get off at their stops," he said. Mr. Mazey called the crowds a plus. "There is more of a selection of females to walk up to and hit on," he said. I usually get a number every time I go out here. "I never call them," he added. But try telling that to Mr. Sabert, who, two hours in, still had not found the seats he was looking for. Around him, some people caroused, while others wrapped pashmina scarves around their heads in a vain effort to drown out the noise. Still he stood on the hurtling train, his Ralph Lauren boat shoes braced against the rumbling floor like a surfer on a board.