LYNN – Police converged on Marian Gardens and then a Western Avenue address Wednesday afternoon in search of several individuals who severely beat a man near the commuter railroad tracks bordering Robert McManus Field.A teenager in the skateboard park next to the field abutting Commercial Street and Neptune Boulevard said the victim, tentatively identified by police as a 30-year-old homeless man, may have been sleeping in trees and bushes along the tracks when one or more assailants attacked him.”He was bleeding from the head,” the boy told The Item.Police Lt. William Sharpe said the man was beaten with bricks or some type of wooden stick. Sharpe said the man was taken to Massachusetts General Hospital with a “possible life threatening injury.”After questioning individuals in the vicinity of the tracks, police launched a search for up to 15 teenaged males, including several wearing black and yellow t-shirts. They also questioned another individual who may have also been assaulted around the time the attack near the tracks occurred.Sharpe asked anyone with information on the attack to contact police detectives and Lt. Thomas Reddy, 781-477-4322.