train
 n.— «The police call it the Neighborhood Enforcement Stabilization Task Force, a unit charged with aggressively enforcing quality-of-life crimes, but people in the neighborhood ominously refer to it as “the train.”…The task force got its nickname because the officers are dispatched into high crime areas and arrive in a caravan, or train, of five to six police cars.» —“Shootings Prompt Call for Change in Police Unit” by Janon Fisher in Newark, N.J. New York Times July 15, 2004. (source: Double-Tongued Dictionary)