On May 20, 2004, the Department of Homeland Security issued security directives requiring measures to be implemented by passenger rail operators. The measures instruct commuter, transit, and inner-city passenger rail systems to comply with requirements that range from removing or replacing station trash cans to utilizing canine explosives detection teams.

The directives, administered by the Transportation Security Administration (TSA), took effect on May 23, 2004. The directives apply to all passenger rail owners/operators, including light rail systems, inter-city passenger rail systems such as Amtrak, commuter rail operations such as the Maryland Rail Commuter and Long Island Railroad, as well as subway systems nationwide.

The directives require rail operators to take a number of steps, among them:

1. Rail owners/operators must designate coordinators to enhance security-related communications with the TSA.
2. Passengers and employees will be asked to report unattended property or suspicious behavior.
3. At certain locations, operators will be requiring to remove trash receptacles, except clear plastic or bomb-resistant trash containers.
4. When needed, canine explosive teams may be utilized to screen passenger baggage, terminals and trains.
5. Facility inspections will be conducted by rail operators for suspicious or unattended items.
6. Rail operators will ensure that security is at appropriate levels consistent with the DHS established threat level.