The federal government will test the feasibility of screening luggage and carry-on bags on U.S. trains and subways, according to Homeland Security Secretary Tom Ridge.

The pilot program was announced in the wake of rail blasts in Madrid that killed more than 200 people, calling attention to security issues with rail systems.

Ridge said the government will not screen the bags of all rail and subway passengers such as those at U.S. airports, but random screening may be examined in high-risk areas or in response to specific threats.

"We are adding several new layers of security that we believe will help reduce vulnerabilities to our systems and make commuters and transit riders more secure," Ridge said. "Clearly, we could provide enough security to put the mass transit systems out of business. Trying to find that balance is something that we need to do."

The pilot program will begin in April or May at an undisclosed commuter rail station.