The Equal Rights Amendment has been endorsed by the Young Women's Christian Association, not the Young Men's Christian Association, as was reported incorrectly last Thursday.

Proponents of the Equal Rights Amendment launched a new drive for passage yesterday with an emotional rally on the steps of the Capitol at which congressional supporters claimed they represent "the thoughtful majority."

"We're here because we think the Equal Rights Amendment is where America is, and we think it is time the political process caught up," Sen. Paul E. Tsongas (D-Mass.) said in announcing that the measure had 51 cosponsors in the 100-member Senate and 201 in the 435-member House. Four more House cosponsors were added later.

The rally, attended by dozens of ERA congressional supporters including House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.), was held two weeks after the original amendment failed to win ratification.

Like so many other ERA rallies since the deadline passed, this one was laced with caustic comments about ERA opponents and much bravado. Rep. Don Edwards (D-Calif.), chairman of the House subcommittee on civil and constitutional rights, claimed the cosponsors represented "an unprecedented, bipartisian coalition."

But there appeared to be little chance that the ERA would advance this year. Despite the impressive number of cosponsors, supporters are still well short of the two-thirds majority needed in the House and Senate for passage.

Senate Majority Leader Howard H. Baker Jr. (R-Tenn.) has said he advocates "a little cooling off," and opposes efforts to bring up a new ERA this year. And Assistant Senate Majority Leader Ted Stevens (R-Alaska), a cosponsor, said yesterday he does not expect Congress to act on the ERA unless prodded by state legislatures.

The first ERA drive died on June 30 because only 35 of the required 38 states had ratified it. Congress approved it in 1972, and extended the seven-year ratification deadline by three years in 1979.

Appearing in the steaming midday heat before a crowd of several hundred on the west front steps of the Capitol, supporters tried to portray the ERA as a mainstream political issue whose time has come. They also read the names of almost 100 groups, ranging from the American Association of School Administrators to the YMCA that have endorsed the amendment.

O'Neill called it "a bread and butter issue" and accused President Reagan of failing to understand the role of women in the American workforce. "Women are in the labor force because they need to work," he said. "They need to work to support their families."

Rep. Peter W. Rodino (D-N.J.), chairman of the Judiciary Committee, is the chief House sponsor. There are 41 Republican and 164 Democratic cosponsors in the House, and 20 Republican and 31 Democratic cosponsors in the Senate. Tsongas and Bob Packwood (R-Ore.) are the chief Senate sponsors.

The pivotal provision in the new ERA is identical to the old one. It states: "Equality of rights under the law shall not be denied or abridged by the United States or by any state on account of sex."