02/19/2008 -Yesterday, Amtrak announced that it will implement improved security measures to prevent a terrorist attack on-board its trains on its Northeast Corridor route between Washington, D.C., and Boston, Massachusetts.

According to CNN.com:

Amtrak passengers will be subjected to random screening of their carry-on bags as part of a new security initiative that will include armed officers and bomb-sniffing dogs patrolling platforms and trains, an Amtrak spokeswoman said Monday.

The Chicago Tribunesays these "mobile security teams" will set up baggage screening areas near boarding gates.  Randomly selected passengers will have their bags screened for trace residue of bomb-making materials using explosive-detection devices. Passengers unwilling to submit to screening will not be able to board the train and will have their ticket refunded.

As the Associated Pressnotes, these security changes are "a significant shift" for Amtrak, which made few security changes after 9-11. However:

Concern about Amtrak security has been mounting since the 2004 bombings of commuter trains in Madrid that killed 191 people. Trains also have been bombed in London, where 52 people were killed in a series of blasts in 2005, most of them on subway trains, and in Mumbai, India, where 200 people were killed in 2006 on commuter trains. Russia also has had several bombings on subway, commuter and long-distance trains.

Amtrak's beefed up security protocols are modeled after methods used in the New York City subway system and will be expanded to cover the railroad's full network after its initial deployment on the Northeast Corridor line.

Amtrak maintains these new security measures are not in response to a specific terrorist threat but to customer feedback that security was lax.

"What we are trying to do is make sure the bad guys know we're out there but don't know where we'll be, or when," Bill Rooney, Amtrak's vice president for security strategy and special operations, said.

Amtrak expects its improved security measures will not result in train delays or passengers having to arrive much earlier at the station before boarding.