The events in London yesterday point up the determination of terrorists to strike at the heart of free countries around the world. The attacks in Madrid and London have focused on vulnerable mass transit systems. The crowds of ordinary citizens who use mass transit and the remoteness of underground trains make such systems tempting targets. In addition to working to prevent such attacks, the challenge is providing swift and clear communication in the event of an attack.

My concern as a regular Metro rider is communication. Whether in a station or a train, the public address system often is inaudible or unintelligible. In the event of an emergency, this system will be vital.

Metro needs to take the necessary steps to ensure that its communication systems are functioning properly and that those making announcements can be understood.

JOHN FICKER

Arlington

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The media should not give the terrorists responsible for the bombings in London any publicity by highlighting their supposed grievances with Western society. The appropriate thing to do is to highlight the bigotry, extremism and incitement that drives these terrorists to kill innocents across the world.

Instead of putting the terrorists' ridiculous demands on the front page, I hope The Post reminds readers about what al Qaeda's vision of an ideal society is: a brutal, misogynist society such as Afghanistan under the Taliban.

DAVID KRUSCH

Washington

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The terrorist attacks on London's transportation system make it clear that we must halt hazardous rail shipments through the heart of Washington.

Deadly chemicals pass over the rail bridge at Second and E streets SW every day. The detonation of one explosive device at the bridge could kill or injure thousands. Rail tanker cars filled with ultra-toxic chlorine and other chemicals could be rerouted around the city, but CSX, the railroad that operates the trains, has refused to do so. The Bush administration supports CSX, a campaign contributor, in its effort to maintain current train routing.

D.C. residents, members of Congress, and federal workers in Maryland and Virginia should protest.

WOODROW LANDAY

Washington

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Will the London bombings awaken this administration and the nation's citizens to the realities of how vulnerable we are to terrorist attack?

While our borders are violated daily by thousands of illegal immigrants, neither Republicans nor Democrats admit this is a security threat. Also, neither party feels a national identification card would do anything other than restrict the "freedom" of our citizens.

Yesterday we were told there will be increased surveillance of trash receptacles in public spaces. This should help the nation sleep better and stop the terrorists in their tracks.

WILLIAM CONTOS

Alexandria