It was a different kind of tea party from the one held 200 years ago in Boston Harbor, but hundreds gathered at subway stations from Ashmont to Alewife yesterday to celebrate 80 years of Red Line T service from Boston to Cambridge.

In what was billed as Boston's "first truly underground music festival," WGBH and the Massachusetts Bay Transit Authority presented events including music, dancing, artistic shows and model train displays at 10 different Red Line T stops.

For two dollars, participants could have unlimited passage between any stops on the Red Line. Harvard Square served as "the mainstage of the days events," with bands performing music from around the world, according to Eric D. Jackson, a WGBH radio personality who hosted the day's events in the Square.

Children attending with their parents were admitted free, with a "Kidfest" in Kendall Square featuring mimes, storytellers, a face painter and a Chinese name translator.

As the day continued, bands such as Hypnotic Clambake, Rescue Squad and Wildest Dreams played at various stations.

Other events included a Model Train Display at Alewife and, at South Station, a demonstration of descriptive video services for the visually impaired.

Jackson said that the program was part of an attempt by WGBH to "be seen in the community rather than being hidden behind walls [of the station office]."

MBTA officials working in the Harvard Square stop noted greatly in- creased activity within the station. As many as200 people gathered to watch and listen to theperformers at some points in the day