(CNN) - At every turn, there are signs that storm-ravaged cities along the East Coast are sputtering back to life despite numerous challenges.
Sounds of trains grinding back to limited service. Buses hauling commuters down roads strewn with debris.
And shivering people, peeking from bulky sweatshirts, waiting hours to fill their gas cans at stations.
But challenges remain, including fuel and food shortages, and lack of electricity to more than 3.3 million customers in 15 states and D.C.
Days after Superstorm Sandy barreled ashore Monday, survivors pleaded for basic necessities.
Donna Solli rode out the storm in her Staten Island home in New York City because she has an elderly dog. She told visiting officials she had not had much to eat.
"One slice of pizza in 48 hours," she said Thursday. "We're going to die ... we're going to freeze. We got 90-year-old people. You don't understand. You gotta get your trucks down here on this corner now."
Sen. Chuck Schumer, who was touring the area, said conditions are grim.
"This is the worst thing I've ever seen, and it's killing me what these people have to go through," the Democratic senator from New York said. "We'll get whatever federal help we can, that's for sure."
A senior administration official said a convoy of 10 Red Cross trucks filled with food, water and medicine arrived Thursday evening in Staten Island.
Superstorm Sandy howled over a series of countries, killing an overall 161 people, including 92 in the United States.
Deaths include two in Canada and 67 in the Caribbean.
New York state, the worst-hit, had 48 deaths, including 41 in New York City, authorities said.
Disaster modeling company firm EQECAT estimates the total economic damage from the superstorm at between $30 billion and $50 billion. The pre-storm estimate was up to $20 billion.
In New York City's borough of Staten Island, the latest deaths included two boys ages 4 and 2, ripped from their mother's arms by floodwaters.
Homeland Security Secretary Janet Napolitano and FEMA Deputy Administrator Richard Serino will travel to Staten Island on Friday to survey recovery efforts.
Meanwhile, authorities scrambled to restore basic services, including hobbled transportation.
Amtrak said modified service resumes Friday between Boston and Washington via New York City. In New York City, limited subway service resumed Thursday. A flotilla of 4,000 buses is taking up the slack.
Neighboring New Jersey, which suffered 12 deaths linked to the storm, plans to restore limited rail service Friday.
In areas where entire neighborhoods remain dark, utilities worked to restore services.
New York City had nearly 500,000 customers without power, including 220,000 in Manhattan.
"We're doing our damnedest to get our power back as quickly as possible," said John Miksad, senior vice president of electric operations at Con Ed.
New York Gov. Andrew Cuomo, in a letter to utilities, warned of consequences if authorities discover they failed to prepare properly.
"Under such circumstances, I would direct the Public Service Commission to commence a proceeding to revoke your certificates," he wrote.
Organizers vowed to hold the New York City Marathon as scheduled on Sunday. Event organizer Mary Wittenberg said the race will not divert resources from the recovery.
The superstorm's wrath also dumped up to 3 feet of snow in West Virginia and Maryland, leaving thousands without power.
The National Weather Service predicted a nor'easter next week from the mid-Atlantic states into New England. But the forecast said the storm would be far weaker than Sandy.
A fizzled Sandy, meanwhile, swirled over Canada.
CNN's Tom Watkins, Mark Meinero and Melissa Gray contributed to this report.