New York City officials say the local bus and subway system should be up and running again within hours, after the Transit Workers Union board voted overwhelmingly Thursday to send the union's 33,000 members back to work without a contract.

The breakthrough came after union leaders were threatened with jail for defying a state law against strikes by public workers. The union is being fined one million dollars each day of the walkout.

Local union president Roger Toussaint told reporters that workers would be back on the job "right away." New York Mayor Michael Bloomberg said union members are being asked to report back to work for their next shift.

The mayor cautioned it will be some 10 to 18 hours before the public transport system is fully operational again. The city's contingency plans, which include high-occupancy requirements for vehicles, will be dropped by midnight local time.

Meanwhile, contract negotiations are expected to continue, as the city and the union haggle over pension and health benefits.