Trolley cars may be riding through Brooklyn once again. Officials with the Department of Transportation say they hope to meet local groups and businesses to discuss the idea of reviving streetcar service between Red Hook and Downtown Brooklyn. Last summer, Mayor Bloomberg backed the prospect of using the city’s old trolley tracks to create new streetcar service in growing waterfront neighborhoods in Queens and Brooklyn, starting in Red Hook. City officials had hoped at the time to begin looking at the possibilities by the end of last year. But the five-month study is only starting now, with federal money secured by Congresswoman Nydia Velazquez. Advocates say the streetcars that once served the neighborhood are cheaper than subways, carry more people than buses, and have zero emissions. Presently, only one bus, the B61, runs between Red Hook and Downtown. Trolley proponents say that this is not enough for an area that has become home to major new stores, including IKEA, and the Brooklyn Cruise Terminal.