Source : MSNBC News FBI investigates suspicious device found in Philly train yard. The Northeast rail corridor is receiving heightened scrutiny from security officials over increasing concerns that the heavily trafficked commuter system is a prime terrorist target heading into this summer’s political conventions, which will be held in Boston and New York. On Thursday night two Acela Express trains, Amtrak’s signature high-speed rail service, traveling from New York to Washington were stopped and searched by bomb-sniffing dogs, an Amtrak spokesperson told MSNBC.com. Nothing was found and the trains were allowed to continue after delays of about an hour, the spokesperson said.