An NYPD truck was outside one entrance, which was guarded and sealed with crime scene tape and open only to security officers.
Authorities cleared Amtrak's main platform area and prevented passengers from entering the area, according to Marcy Golgoski, an Amtrak official.
Police, including at least four wearing hazardous materials suits, searched a roped-off area near the Amtrak facilities.
more here:
http://www.cnn.com/2005/US/10/07/newyork.subways/