NEW YORK - A federal judge Friday upheld the police department's practice of randomly searching subway riders' bags, saying the intrusion on people's privacy is minimal while the threat of a terrorist bombing is "real and substantial." Police tightened security in the nation's largest subway system in July after the deadly terrorist attacks in London's underground. "The risk of a terrorist bombing of New York City's subway system is real and substantial," U.S. District Judge Richard M. Berman said. The New York Civil Liberties Union had challenged the searches, arguing that riders were being subjected to a pointless and unprecedented...