If you're passing through some of the busier subway stations this morning and notice a lot of police presence, it's not just because of the beefed up security—the NYPD is conducting a transit drill with other agencies. According to 1010WINS, "Police say the three hour exercise will start at 7 a.m. and involve about 100 NYPD officers. They'll be noticeable at Penn Station, Herald Square Station and Grand Central Station. Police officers from Amtrak, the Metropolitan Transportation Authority, New Jersey Transit, Port Authority and the Transportation Security Administration will also take part." And, if you can believe it, the drill was reportedly scheduled before the Moscow subway station bombings.