Despite their casual appearance, the harpists, saxophonists, classical guitarists, and various other street musicians who play during rush hour in the Square and Government Center subway stops have their performances scheduled by a Cambridge cultural clearinghouse.

The Cambridge Multicultural Arts Center books sports for six hours each weekday at two "T" stops that performers consider to be financially lucrative and a chance to get other jobs.

In its seventh year, the "Music Under Boston" program offers free permits for three-hour gigs between 7 and 10 a.m. and 4 and 7 p.m. David Kronberg, executive director of the city center, said that officials hope to expand the scheduling to include more hours and six more stations.

But according to Kronberg, musicians scramble for spots at the stops currently scheduled. "Harvard Square is enormously popular," he explained. "We book on the first day of the month and usually within the first five hours we've scheduled the entire month."

He attraction to the Square comes from the money available--Kronberg estimated that the musicians make from $20 to $50 in each three-hour show--and the opportunity for exposure that can lead to other employment.

"A lot have gotten other gigs and one was 'discovered' by an RCA Records representative and hired as a studio musician," said Kronberg.

Musician David Gilden said he has been hired to perform at several weddings after people saw him in the newly renovated Square station.

Too Much Rush

David Neiman, who plays the hammered dulcimer at the Church St. stop, said he thinks the scheduling should be expanded. "People then would have time to stop for a minute and listen," he explained. "At rush hour they are in too much of a rush."

He added that the benefits of performing underground go beyond profit. "It's nice to have someone come up to you and say you helped make going through the subway more pleasant." Nieman said "Just a smile from someone makes it very enjoyable."