The Washington Metropolitan Area Transit Authority (WMATA) began ramping up security on Thursday as a precaution after news of a foiled terror plot in London. WMATA police began doing random sweeps of stations, trains and buses, as well as MetroAccess vehicles and other transit facilities. It also closed all public restrooms in rail stations, increased security announcements and dumped trash cans more frequently. “There is no threat to mass transit, but it’s prudent to step up security given that mass transit has been a terrorist target in the past,” said Polly Hanson, police chief for the agency.