“Last call!” Rabbi Moshe Langer shouts into a microphone.

He scans the crowd in San Francisco’s classic mobile symbol, the cable car. The passengers come from all over the world — Missouri, Brazil, Greece, Sweden — and many carry the digital camera that has become a staple for tourists.

Langer has hooked them up with a free tour of the city’s highlights. Their fare on the 1977 motorized cable car? A promise to do a mitzvah.

“This is the acts-of-goodness-and-kindness tour of our city,” he tells a young couple from New York City. “Welcome aboard.”

Langer took on the cable car project upon returning to San Francisco from rabbinical school in Florida. His goal is to inspire a domino effect of good works. For example, if a rider pledges to volunteer or to be kinder to their family or donate some clothes, and shares the experience with a friend, that person, in turn, may inspired to do something good, too.

While the tour is not explicitly Jewish, save from Langer’s explanation that Dungeness crabs at Fisherman’s Wharf are not kosher, the center section of the cable car is filled with books and newsletters about Jewish thought, just in case a rider is curious about Chabad and Judaism.

“Random acts of goodness and kindness bring redemption,” Langer says. The cable car is simply a vehicle to carry out the directive of the Lubavitcher rebbe, Rabbi Menachem Mendel Schneerson, to bring the world together in peace.

So will the cable car accomplish world peace? Chabad of S.F. is optimistic, but also realistic.

“It’s a step,” says Rabbi Yosef Langer, Moshe’s father and head of Chabad of S.F.

Maury Polste, Yosef Langer’s brother-in-law and holder of a commercial driver’s license, drives the cable car, which departs at 2 p.m. Mondays and Wednesdays from the corner of Geary and Powell streets. Chabad eventually hopes to offer tours daily.

Tourists stroll down Geary’s wide sidewalk, clutching shopping bags and MUNI maps. Many do a double take at the cable car, inquire about the vehicle (“It’s free?” they ask incredulously) and hop onboard.

On this day in late May, 15 people have joined Moshe Langer and Polste for a free tour. As the cable car pulls away from the curb, Langer reminds everyone on board to “think of something you can do to bring peace into the world.”

The car drives up Grant Street, through Chinatown, and turns on Columbus Avenue. It meanders through North Beach, past the wharf and Russian Hill, with views of the Marin headlands and Golden Gate Bridge.

“There was such a long queue for the real cable car,” says Gunilla Fredya, of Stockholm, Sweden, who is on the tour with her infant son, David. “It’s lovely they’re doing this without getting paid. It makes people happy. I’d like to do the same.”

The cable car tours began in April. It costs Chabad about $7,500 each month to maintain and operate the vehicle, money that Moshe Langer is still trying to raise.

Langer said he also is learning more about San Francisco’s Jewish history to make the tour more Jewish. However, the focus of the tour will remain the city’s scenic and historic landmarks, and encouraging tourists and riders to think about being better people.

“I’ve done good all day,” says Mark Sexton, a Paul McCartney-lookalike from Missouri. “I let an old lady have my seat on the bus and I gave a homeless man money.”

Before he stepped off the cable car, Sexton recorded those deeds in a yellow legal pad attached to a clipboard. Chabad keeps it as a record of the good works they inspire.

When the tour loops back to Union Square, the cable car stays at the curb for an additional half-hour, during which time a dozen people approach Langer and inquire about the tour. He tells them to come back next week for a free ride. And in the meantime? Do something good.

For more information about the Chabad cable car, email [email protected] or call (415) 668-6178.