NEW YORK -- A revised design for the World Trade Center memorial was unveiled yesterday and includes a subtle tribute to the rescue workers and an underground room where visitors can see twisted steel beams, a crushed fire truck and other artifacts from Sept. 11, 2001. The additions received a warm response -- a distinct change in the often contentious process of remembering the nearly 3,000 victims of the terrorist attacks.

"These revisions show that the Sept. 11 families and the general public have finally been given a voice in this process," said Coalition of 9/11 Families executive board member Patricia Reilly, whose sister died in the attack.

Construction on the memorial is expected to begin by the end of this year.

One of the changes to Michael Arad's Reflecting Absence memorial addressed the sensitive issue of whether rescue workers should be singled out in some way.

In the new design, Arad places all of the victims' names randomly around two reflecting pools, a visual reminder of the "haphazard brutality of the attacks," but he designates rescue workers by listing their ranks and agency's insignia alongside their names.

Police Commissioner Raymond Kelly and Fire Commissioner Nicholas Scoppetta said they were satisfied with the tribute.

"This is a simple, elegant, quite dignified way to remember," said Scoppetta, whose department lost 343 members when the twin 110-storey towers collapsed.

The revisions also add a forest of trees, benches and grass to what was once open space and place a cultural centre at the northeast corner of the site.

Underground, an interpretive centre will include lecture rooms, a research library and pieces from the ruins. Some critics of the original design complained that it did not get across the horror and violence of the attacks.

The new design also features a ramp leading down to the museum that passes exposed parts of the slurry wall, the last remnant of the tower complex.