Lauren Wasserman and Christopher Clark participate in their 'first dance' on their wedding day at the Intercontinental Harbor Court Hotel in Baltimore. (Joe Brier, The Happy Couple/JOE BRIER, THE HAPPY COUPLE)

Emotions were running high for Lauren Wasserman the day before her 27th birthday in September 2008.

The public relations manager was excited to be taking the train from Washington to her hometown, Baltimore, where she’d spend the weekend celebrating with family. But this birthday was a fraught one. She was entering her late 20s, was yet to have a serious boyfriend and had begun to wonder about her prospects for romantic happiness.

So as she waited in the Amtrak line at Union Station, she called a friend to discuss. Wasserman mentioned that a guy she’d known for a long time was single. “Maybe I need to marry him?” she wondered.

As she took her seat on the train, Wasserman was so engrossed in the conversation that she barely noticed when a man sat next to her. And when he tapped her on the shoulder 45 minutes into the ride, she assumed it was to ask her to lower her voice.

Instead, her seatmate showed her a magazine cover on which he’d written: Will you go out with me? Circle one. Yes. No. Maybe.

Lauren Wasserman and Christopher Clark (Joe Brier, The Happy Couple)

Christopher Clark had noticed Wasserman in line and angled to sit next to the pretty blonde. He knew from her conversation that she was single and assumed he’d have a chance to talk to her once she got off the phone. When it began to seem as thought that might not happen, Clark — not normally the forward type — asked a fellow passenger for a pen and decided to be direct. “That’s not like me at all,” says Clark, an engineer who was 23 at the time. “I’m not that out of the box.”

Wasserman was flabbergasted — and flattered. Clark looked young, but he was very cute. She hung up the phone, and the two chatted as the train approached Baltimore. Before she left, she circled yes and wrote down her name and number.

Wasserman nearly floated off the train. “It was exactly what I needed — the confidence booster I needed,” she says. She decided that even if he never called, it wouldn’t matter “because it was such a great story.”

But three days later, he called and left a voicemail. Nervous about a phone conversation, Wasserman texted back. They decided to meet for dinner downtown at Cafe Asia.

Wasserman’s anxiety built throughout the day of the date. But as soon as they sat down, her jitters drifted away. “I was instantly calm and just like myself, which is weird because normally on first dates you’re not totally yourself,” she recalls. “We were laughing a lot.”

They stayed for hours, but when Clark offered to walk her home, Wasserman froze and awkwardly declined.

“I always got nervous at the end of dates,” she says. “I was like, ‘I hope I didn’t mess this up.’ ”

At the urging of a co-worker, she texted Clark the next day to say she had a great time. He was relieved to hear from her after the abrupt goodbye and offered to cook dinner for her the next week. Wasserman was still worried Clark might be significantly younger, so as they sat on his couch she asked his age. She sighed when he said 23 — he was younger, but not scandalously so.

Wasserman was sure he’d kiss her after walking her to the Metro. But as the train approached, he didn’t make a move, so she leaned in and planted one on his lips — then spent the rest of the night fretting that she’d been too forward. “I was like, ‘Oh my God — why did I do that? He must’ve hated that.’ ”

He didn’t hate it. By Columbus Day, he would tell his sister that he’d found “the one.” Wasserman was easy-going, sweet and had “the purest heart of anybody I’d ever met.”

Wasserman is high-energy and hard-charging, but with Clark she was calm and comfortable. “And every single person who meets Chris says he’s the nicest person on the planet and adores him,” she says. “So it was constant affirmation that I was on to something.”

They seemed compatible in almost every way except religion. Wasserman told Clark, who was raised a practicing Catholic, that it was important to her that her children be Jewish. They grappled with the issue on and off for two years until Clark decided he would feel okay raising Jewish children. “I think we both realized it’s not extremely important what you believe in as long as you believe in something,” he says.

In August 2011, Clark and Wasserman vacationed with his family in Cape Cod. For two days he carried a diamond ring in his pocket until he found a private moment by the bay and got down on one knee to propose. A few months later, they sent out a save-the-date in the form of a train ticket, commemorating the way they met.

“We have a love-hate relationship with Amtrak,” Clark says. “It’s always delayed — but we can’t be too mad.” (Wasserman, meanwhile, thinks the train company should offer a “singles car” so that unattached passengers can mingle as they travel.)

On Nov. 3, Wasserman and Clark were married under a chuppah at Royal Sonesta Harbor Court in downtown Baltimore. Members of an a capella group to which Clark belongs sang during the ceremony, and his father and uncle played piano for the cocktail hour.

The two often look back on that first train ride with wonder at how far it’s brought them. “I think it’s amazing,” Wasserman says.