The United States' largest mass transit system endured its first strike in a quarter-century yesterday, stranding seven million riders in the December cold as negotiations remained stalled and a Brooklyn judge imposed a 1 million US dollar a day fine on the striking union. State Supreme Court Justice Theodore Jones leveled the sanction against the Transport Workers Union for violating state law by going on strike. Attorneys for the city and state had asked Jones to hit the union with a "very potent fine" for ignoring the Taylor Law.

Subways and buses were shut down as transit workers walked off the job.

The city survived the morning rush without the anticipated gridlock and widespread chaos as many commuters adapted to the absence of mass transit - some by just staying home.

The 33,000 members of Transport Workers Union officials say transportation workers deserve a better contract, especially considering that the MTA had a budget surplus of 1 billion this year.

Union attorney Arthur Schwartz accused the MTA of provoking the strike - a charge that Governor George Pataki disputed.

"The TWU has broken the law," Pataki told a Manhattan news conference.

Authorities began locking turnstiles and shuttering subway entrances shortly after the TWU ordered the strike, and commuters struggled through a rush hour filled with disorder.

PHOTO CAPTION