The service had been operating on a 24 hour a day, 7 days a week schedule.
The city blames the state legislature's failure to pass a temporary 1 per cent increase in the city's sales tax and changes in the city's pension obligations.
The state Senate on Wednesday approved a bill that would overhaul state laws governing municipal pension funds and generate $700 million to avoid massive layoffs and service cuts in Pennsylvania's largest city.
The 38-9 vote followed brief statements by senators who supported the measure, which would require House approval before it could be sent to Gov. Ed Rendell to be signed into law.
A spokesman for House Speaker Keith McCall, D-Carbon, said the House is unlikely to convene this week. House members need time to review the complicated municipal-pension changes in the Senate bill, spokesman Bob Caton said.
Both the Senate measure and a bill that the House passed earlier this month would give Philadelphia officials tools they have sought to balance the city's budget - the authority to increase the local sales tax from 7 percent to 8 percent for five years and permission to defer a portion of the city's pension contributions.
The House bill dealt exclusively with Philadelphia's problems. The Senate legislation will affect all of Pennsylvania's more than 3,000 municipal pension funds, setting up a system that combines relief measures with regulatory intervention, including a state takeover of funds with the most serious financial problems.