The long-running New York protest against economic inequality and perceived Wall Street excesses gained momentum Wednesday as union members joined marchers in Lower Manhattan, while students at several colleges walked out of classes in solidarity and like-minded organizers completed plans to bring the fight to Washington.

Since beginning with a few dozen demonstrators in New York on Sept. 17, the Occupy Wall Street protests have not only grown, but have become increasingly organized, offering medical aid, legal help and a newspaper.

A similar protest decrying the “corporate machine” is slated to begin in Washington on Thursday, with organizers advertising a noon concert and rally on Freedom Plaza. “Stop the Machine! Create a New World,” read online fliers calling protesters to bring sleeping bags to 13th Street and Pennsylvania Avenue , “where we will NONVIOLENTLY resist the corporate machine by occupying Freedom Plaza to demand that America’s resources be invested in human needs and environmental protection instead of war and exploitation.”

The protest’s Web site ( lists more than a dozen people principally responsible for organizing the protest, among them community and peace group organizers, a pastor, a feminist, an environmentalist, a “rabble-rouser” and a pediatrician who quit her practice to advocate for governmental single-payer health care. Many more organizations are listed as supporters committed to bringing members to the protest.

In New York on Wednesday, people marched from Foley Square to Zuccotti Park, the protesters’ unofficial headquarters.

Sterling W. Roberson, vice president for the United Federation of Teachers, said union members shared the ideals of activists who have been camped out in sleeping bags for more than two weeks. “The middle class is taking the burden, but the wealthiest of our state and country are not,” he said.

Karen Higgins, a co-president of National Nurses United, came with a group of colleagues from Boston. She said they had seen patients who skipped important medical tests because they couldn’t afford them.Roxanne Pauline, a coordinator for the Northeastern Pennsylvania Area Labor Federation, said some of her union’s members plan to stay in Zuccotti Park over the weekend.

The protesters have varied causes, but have reserved most of their criticism for Wall Street. They’ve spoken out about unemployment and inequality.

One of the larger protests outside New York on Wednesday was in Boston, where about 200 Northeastern University students gathered on campus to condemn what they called corporate control of government and the spiraling costs of their education.

Hundreds of college students at New York’s sprawling public university system walked out of classes Wednesday afternoon.Protests were scheduled at State University of New York campuses in Albany, Buffalo, Binghamton, New Paltz and Purchase.

Danielle Kingsbury, a 21-year-old senior at New Paltz, said she walked out of an American literature class to show support for some of her professors who she said have had their workloads increased because of budget cuts.

— From news services and Washington Post staff writers