By Mike Dunn

PHILADELPHIA (CBS) — Much of Philadelphia will remain shut down Tuesday, and city officials plan a full assessment of the damage brought by Hurricane Sandy. The key question: when will SEPTA be able to restore operations?

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For his part, Mayor Michael Nutter is not optimistic of any SEPTA service coming back on line Tuesday.

“Probably most of the afternoon there will not be service either,” the mayor says, “No one should be anticipating riding SEPTA at any point in time.”

Nutter says do not expect any resumption of SEPTA service until crews conduct a full assessment of facilities, equipment and infrastructure.

“Only after that assessment has been done,” he says, “and only when they are sure they will be able operate the system with complete safety, will they try to bring any of the lines back up.”

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SEPTA General Manager Joe Casey says as the storm system moves on his team will move in, taking a look at the extent of possible damage.

“This is a laborious process,” Casey says. “It takes hours to examine the system completely, six to eight hours.”

Whenever the all clear is reached, the first SEPTA service to be restored would be the Market-Frankford El and the Broad Street subway, followed by buses and trolleys. The regional rail lines will not operate today as those trains share tracks with Amtrak, which remains shut down.

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