As she bounced along all 14 cars, knocking into people here and squeezing past other people there, Buono introduced herself - some didn't know who she was - and hugged longtime friends and political associates.
In the bar cars, where the train's "booze cruise" reputation was upheld, she heard a welcome chorus: "Governor Buono!"
"People are more interested in talking to me" this year, said Buono, a lawyer known for her maverick streak. "That goes to the point that, in politics, anything can happen."
She may have a bumpy ride ahead. One poll shows Christie with 78 percent approval ratings. Even most Democrats support him, another reports.
And in a state that requires that candidates put up TV ads in the pricey Philadelphia market and even pricier New York market, Buono's campaign had less than $250,000 in the bank last month compared with Christie's $2.1 million.
Also uncertain is how much support, in cash and get-out-the-vote effort on Election Day, will come from the unelected Democratic bosses who control the political game.
Ironically, Christie has better relationships with Democrats than Buono does. They have worked with Christie on issues and helped the governor pass major legislation, while Buono showed her independent side in 2011 by bucking party elders and opposing a Christie-backed plan to cut public-employee benefits.
"I may have ruffled some feathers in the past," said Buono, 59, a mother of four and stepmother of two. "I don't know if that's a bad thing."
So it was something of a coup for the 18-year lawmaker to have wrapped up the nomination more than four months before the Democratic primary. (A few other Dems are running, but they lack money and name recognition.)
If her party wants a contrast to Christie, that's what they get in Buono - both physically (she's petite) and ideologically (she's unabashedly liberal).
Buono is running on pocketbook issues: property taxes, foreclosure rates, and unemployment numbers that are among the highest in the nation.
"I'm out there talking to people, and there is more than a discontent - there is a malaise," she said. "On every economic measure, the governor's record is one of failure."
Christie, who headlined the Chamber of Commerce dinner Thursday night (Buono skipped the speech), is campaigning on a message of bipartisanship coupled with reminders of his leadership in the aftermath of Sandy.
His post-Sandy popularity is formidable, and that's why many Democrats are privately skeptical of Buono's chances. There's concern she might even lose by a double-digit percentage, putting at risk down-ballot Democratic legislators up for reelection.
"Gov. Christie connects with the people of New Jersey like no other leader in recent history, and he connects with people all across the political spectrum," said Michael DuHaime, Christie's political adviser. "He is a true New Jersey leader, and voters in this state know the real deal when they see it."
Because of Christie's high profile, the race will be in the national spotlight, Buono acknowledges. She met with the Democratic Governors Association in Washington last week and hopes to attract Democratic dollars from around the country.
Though she doesn't have Christie's natural, shoot-from-the-hip sense of humor and ease in front of a microphone, Buono - who runs daily to ease stress - is poised and telegenic. As the first female Senate majority leader in state history, a post she lost last year, she has broken ground for women. And she has an up-from-the-bootstraps story that includes a stint on public assistance, and government loans that got her through college and Rutgers-Camden Law School.
Assemblyman Albert Coutinho (D., Essex) watched Buono work and walk the train last week. It's still nine months until Election Day, he noted, "an eternity in politics."
"And as you can see," Coutinho said as Buono jostled through the crowd, "she's going to fight every day."
Contact Matt Katz at 609-217-8355 or email@example.com,
or follow on Twitter @mattkatz00. Read his blog, "Christie Chronicles,"
at www.philly.com/ christiechronicles.