5:40 p.m., Grand Central

It’s Friday. A whisper-thin man in a tailored suit leads the stream of New York commuters down the platform. His rolled-up shirtsleeves and the can of Stella Artois in his left hand indicate that we have the same destination in mind. The further we tread, the more I question whether it still exists. And then I see it: the small white placard with bold red lettering that reads “Bar Car.” I’ve arrived at the last bar car on any commuter line in America.

5:51, En Route

Dan, the bartender, has been serving the drinks offered on the hand-scrawled menu taped above the bar for the past 10 years. “Tanqueray or Beefeater?” he yells to me over the commotion of 100-plus chattering passengers in the Metro North Railroad’s New Haven line bar car. Danny, as the loosened-tie regulars call him, passes me a clear plastic sippy cup of gin and tonic, with two red straws, a lime, and a lid. “Hey Tom.” Danny pulls a Coors from under the bar before the man behind me even places an order. “$6.75,” he says, turning back to me.

Across from the bar, 42-year-old New York consultant and Westport dad Jerry Doyle leans his elbow against a side table scattered with suit coats and briefcases. Jerry is one of the regulars who receives daily text messages from Danny with information on which evening trains will have a bar car. (Today’s text, from 3:18 p.m.: “548 611 705 807 and the 531 and 614 stamford locals.” By 4:21 p.m. the Clever Commute Twitter account @cc_mnr_bar_nh tweets the same message.) In short, Jerry knows the culture of the place. “It’s mainly a Wall Street crowd during the week, but on Fridays it’s more like a rough Irish pub,” he says with a smirk.

“No, no, it’s more like ‘Cheers’ around here,” a Wall Street investment banker and Fairfield husband calls out from the corner of the bar. He and three other men are playing dice. All four have been riding the bar car home together almost every evening for the past 20 years. “Cheers,” the late 20th century sitcom set in a neighborhood bar, seems a fitting reference. For the regular riders, the Metro North bar car recalls the title of “Cheers’” famous theme song, “Where Everybody Knows Your Name.” Or at least they know your first name and drink order.

6:32, Stamford

The train makes stops, but the laughter, drinks, and dice continue to roll. Beyond the bar stands a group of six men in their mid-to-late 30s drinking from cans of Coors. One of the men, Mike, has been making business deals and friends in the bar car on his ride home to Westport since 1988. Like all of the regulars, this group is part of a tradition that began in the 1930s with what was then called the counter car.

“The car is a traveling restaurant, night club, dance floor, liquor store, and what-not, all in one,” Hartford Courant reporter Jack Zaiman wrote in 1936. “Here the patrons chummed together, strangers all like old friends.”

Dressed all in white, bow-tie wearing bartenders Sam and Eddy stood in stark opposition to their black-suited customers in top-hats who ordered everything from ham and eggs to whisky sours. On Sunday afternoons, weekend excursionists returning to Connecticut sang along to the well-known tunes played by Andy the accordionist. The confidence gained when drinking was the secret of the “nimble-footed” passengers who danced while the train sped on at 45 miles per hour, according to Zaiman.

With the success of the original counter car, bar cars expanded to rail lines in cities like Chicago and Milwaukee. Facing concerns of intoxicated passengers, hard economic times, and demands for additional seats, all other commuter bar cars have been pulled from the tracks. Many newspaper columnists and regular commuters discuss the potential for the New Haven line bar car’s last call. Even Danny the bartender says the car’s future is uncertain. But according to Jim Cameron, chairman of the Connecticut Rail Commuter Council, the railroad has committed to maintaining the bar car.

In 2012, Danny doesn’t wear a bow tie, customers cannot order breakfast from the bar car, and an accordionist no longer plays on the daily ride. Still, Mike and his friends continue the almost 80-year legacy. On their ride home, they place bets on the weekend’s basketball games, compare kids’ sports schedules, and discuss what to get their wives for upcoming anniversaries and holidays — sharing conversation as they do almost every Friday.

6:49, Westport

“Happy weekend all you humps,” Danny the bartender yells as he exits the bar car. The few remaining commuters sip the ends of their drinks and slip back into their suit coats and high heels as the train rolls towards the suburbs.

6:59, Fairfield

“Fairfield, transfer available to the New Haven line,” the conductor announces. It’s the first time I’ve heard him on the overhead speaker all night.

The Wall Street investment banker and Fairfield husband stands alone by the empty bar, glancing over a worn New York Times. He turns to me as we step off the train into the cold night air of the Connecticut platform.

“Remember kid — it’s like Vegas. What happens on the bar car, stays on the bar car,” he says to me, knowing I’d only taken the ride to write this story.