A woman has been arrested for abandoning her newborn daughter on a rush hour subway platform at Penn Station in Midtown Manhattan, police said Wednesday. Assa Diawara, 30, was nabbed late Tuesday for allegedly leaving the infant at the foot of a staircase on the downtown No. 1 train platform at the 34th St.-Penn Station stop about 9 a.m. Monday. The baby is her daughter, police sources said. NYPD detectives conducting an exhaustive search of surveillance footage in Midtown captured images of Diawara bringing the newborn into Penn Station and then leaving without her, the sources said. Surveillance video showed...