Today, those of you passing through big transit hubs, like Grand Central, Penn Station and Herald Square, may seem more police officers and other law enforcement agencies in force. That's because it's the second big transit drill involving the NYPD (including its Counterterrorism, ESU, K9, Transit and plainclothes units); police from Amtrak, the MTA, the Port Authority, and NJ Transit; the National guard; the TSA; and NY State's Homeland Security. According to WABC 7, "Beginning at approximately 7 a.m., commuters will experience increased police presence; bag screenings and inspections of train and subway cars." The last drill was in April.