A Platform That Attracts Many Mayoral Candidates Bill de Blasio, a Democrat running for mayor, outside a subway stop at 96th Street and Broadway in Manhattan. Stay away from the MetroCard machine. Do not block the staircase. And please: pick up your pamphlets before they flutter onto the track and cause a fire. The subway stop meet-and-greet is a time-tested tradition in New York City mayoral races, an efficient, photo-friendly way for candidates to pitch to a self-replenishing crowd of voters. But the Metropolitan Transportation Authority, bracing for an influx of handshaking politicians (and their sign-toting aides), has a few rules. Campaigning on a subway car is verboten. Politicians generally must remain at least 25 feet from station booths or ticket kiosks. Amplified sound is not allowed. And the movement of passengers cannot be impeded - transit officials occasionally urge campaigns to reconsider a location to avoid pileups. The transportation agency also has a blunt message for leafleteers. "Pick up your fliers," Adam Lisberg, the M.T.A."s chief spokesman, said. People are going to slip and fall, and they're not going to sue John Liu's campaign - they're going to sue us. With 468 stations to choose from, candidates have their own strategies for finding an ideal place to press the straphanger flesh. Blocking the egress is a no-no - commuters may blame a bottleneck on the candidate. Stu Loeser, a former press secretary for Mayor Michael R. Bloomberg, said that finding a spot with two entrances was usually best. "People who don't want to be bothered by the handshake can just skip it," he said. The candidates who give regular people an easy out generally prove more popular. Afternoon commutes can be more fruitful than the morning ones, since passengers are less groggy and less distracted. It turns out that few New Yorkers want to stop and chat with someone who could be the most powerful mayor in the country when they are late to a morning meeting. The other key is finding commuters who actually vote. Grand Central is not ideal because many people there are commuters headed out of the city. There is no official count of subway appearances in the current campaign, but a review of public schedules from the last few months turned up a few trends. Manhattan and Brooklyn stations predominate. The only candidate who has regularly appeared at stations in the Bronx is Adolfo Carrión Jr., the Independence Party candidate and a former Bronx borough president. Traditionally, candidates are drawn to neighborhoods with high voting rates and opinionated residents. The Upper East Side station at 77th Street and Lexington Avenue (which happens to be Mr. Bloomberg's home station, although he does not use it much) is a popular choice. The 72nd Street station on the Upper West Side is considered ideal, being situated inside a small park and close to popular destinations like Fairway and Trader Joe's. "We want a busy, busy station," said Bill de Blasio, a Democratic candidate, as he greeted voters outside the station at West 96th Street on Wednesday afternoon. He gestured toward the wide ramp that leads to the station's plaza in the middle of Broadway: "This has a perfect funnel dynamic." Mr. de Blasio, who has visited a half-dozen stations in the past week in Brooklyn, Queens and Upper Manhattan, gave high marks to the sizable awning at 96th Street - useful since commuters were taking cover there as a rainstorm soaked the streets. He posed for iPhone photos with some passing admirers, and jumped at a chance for some impromptu chivalry, untangling a woman's umbrella from another commuter's necklace. Mr. de Blasio was also mindful of the need to catch a train, manhandling a bespectacled staff member out of the commuters" way. Aurora Nonas-Barnes, a teacher and performer from Harlem, waited in a line for five minutes to speak with Mr. de Blasio, and told him she was impressed with his ideas for the city. "He's not handing out umbrellas, but we won't hold that against him," she said. The subway being a kind of civic arena, candidates can field some unusual questions. Charles Gross, an Upper West Sider who works in real estate, said he asked Mr. de Blasio about the city's bedbug problem and suggested bringing back DDT, the banned insecticide spray, as a solution. How did Mr. de Blasio respond? "He was noncommittal on that," Mr. Gross said. Mr. Lisberg, the transit authority spokesman, was asked if the subway system might consider adding a new onboard announcement to warn customers about the impending flood of would-be mayors. Mr. Lisberg said there were no such plans, but gamely suggested a potential script: "Ladies and gentlemen, political candidates are allowed on station platforms. Please be cautious. Alison Leigh Cowan contributed reporting. An earlier version of this article misstated the connection between the Bronx and Adolfo Carrión Jr., a Democratic candidate for mayor. He is a former Bronx borough president, but he is not a native.