All aboard the “L” train!

Brooklyn matchmaker Erika Christensen, 31, calls herself the “Love Conductor” — because she spends her days trainspotting single straphangers she thinks are ready for romance on the rails.

In one recent outing she spotted a man in his 20s selling paintings on the platform of the Bedford Avenue station in Brooklyn.

“Are you single?” she asked bluntly, pulling out her business card — “You’ve been spotted,” it reads — and handing it to the slightly startled man.

“If he gets in touch, I have a couple girls I can fix him up with,” she said confidently.

The gorgeous Greenpoint resident has managed to combine her matchmaker skills with her other passion — the New York City subway system and its underground culture — into a budding career.

A dozen clients pay her between $39 and $456 a month for matches, date planning and coaching services. Rather than scour Web sites or bars, she rides the rails looking for someone’s perfect match. For about a month, she’s been selling her services in conjunction with the dating site Tawkify, which her blog Train Spottings is now part of.

“I’m using the subway as this great recruitment tool,” she says. No surprise: The L train, with its contingent of single hipsters, is one of her more fruitful stomping grounds.

Sarah Nisbett, 30, was riding the F train sketching other passengers last month when Christensen approached her. Nisbett was instantly on board, hoping the Love Conductor would help track down her elusive dream man — a funny, artistic lumberjack.

“It’s a totally natural idea for New York,” she says. “There is that little nugget of hope that makes commuting more exciting.”

If Christensen makes a match, she’ll coordinate the date, which could be anything from a subway ride on the 6 train to a rendezvous at the abandoned but beautifully ornate 1904 City Hall station to drinks at the Campbell Apartment bar in Grand Central Station.

Christensen has even been known to jump in and interrupt a potential missed connection.

“I don’t know if you people are single, but you are clearly enjoying the sight of each other,” she’ll say before handing out her card and leaving the train.

Christensen, who grew up in a small West Virginia town with a one-room schoolhouse, has been fascinated by the subway’s underground culture since moving to New York in 2004 to work for a financial company. She says the New York subway system is the ultimate meet market, we just need to put down the iPhones, the books and our guard to make it work.

“You’re lying if you say you’re not checking everyone out on the train,” she says.