An electrical malfunction outside New York City brought train service to a standstill Wednesday and spotlighted problems on Amtrak's Northeast Corridor that persist despite a long-term effort to upgrade its aging power supply system.

Trains from Boston to Washington were delayed for about three hours after a low voltage reading was detected near a substation in North Bergen, N.J., where trains go under the Hudson River en route to Manhattan. Thousands of commuters and holiday travelers were stranded or left scrambling for alternative transportation.

"It's pretty awful," said Nick Fesette, 22, whose duffel bag rested on the floor of New York's Penn Station next to two white garbage bags full of wrapped gifts for his family in upstate New York.

Service was restored at about 11:30 a.m., and trains were running at or close to schedule by about 4 p.m.

Electrical problems are nothing new on the Northeast Corridor, by far Amtrak's most heavily traveled route.

Three disruptions occurred within a month in 2006. The worst, on the Thursday of Memorial Day weekend, stranded tens of thousands of passengers for up to four hours, some in sweltering tunnels. That was blamed on problems at power stations and substations built in the 1920s near Philadelphia.

On the Sunday before Thanksgiving in 2007, damage to overhead wires near New York disrupted service for about 2 1/2 hours.

Five years earlier, Amtrak embarked on a long-term program to modernize dozens of substations along the Northeast Corridor, some dating to before World War II.

The program received a boost this year when Amtrak earmarked more than $60 million to upgrade its power supply system on the Northeast Corridor. The money came out of $1.3 billion in federal stimulus money for Amtrak to upgrade infrastructure and put more railcars in service.

Amtrak has historically had to fight to receive funding from Congress. Last year, President George W. Bush threatened to veto a bill to fund Amtrak for the next five years unless the railroad was held more accountable for its decisions.

"When Amtrak, one of the most vital transportation links on the East Coast, is habitually underfunded, not even an outage as widespread as this one can be considered a surprise," Sen. Chuck Schumer, D-N.Y., said Wednesday. "We are more dependent on Amtrak than ever, and Congress should step up to the plate to fund it at the right level."

Spokesman Cliff Cole said Amtrak was investigating Wednesday's malfunction and there was no indication human error caused it, but that extreme weather can affect the electrical system. Weather across the region Wednesday morning was seasonally cold but mostly clear.

Trains can run at low voltage but are routinely moved to the nearest station to avoid a larger power failure, Cole said.

"If you continued to move at normal operations with low voltage, the danger is we could have a complete outage," Cole said.

Cole could not say how old the North Bergen substation is or whether it is slated for upgrade. An improvement to the substation and the construction of another in North Bergen is being considered as part of an $8.7 billion project to build a second tunnel from New Jersey to Manhattan.

During Wednesday's stoppage, travelers packed a waiting area at Penn Station in New York City, sitting on suitcases with bags of holiday gifts scattered around them. A display board showed grim news for every train.

Lyn Hunt and four relatives had been traveling since Saturday — or trying to. Their trip to Newark from England had to be rerouted through Chicago because of the weekend snowstorm that swept the East Coast.

The family then traveled by Amtrak from Chicago to New York, only to be delayed again Wednesday as they tried to take a train north.

"We've decided that our motto is adapt, improvise and overcome," Hunt said. "We don't know yet how we will adapt or overcome this."

Her answer came just before noon when an announcement crackled over the loudspeaker that power had been restored and trains would begin rolling again.

Late Wednesday afternoon, Paul Adent, a personal trainer from Santa Monica, Calif., traveled from New York on an Amtrak train that arrived in Boston about an hour late.

He said he couldn't find a seat on the train, so spent the 3 1/2-hour ride in the bar car. Adent, who came to Boston to visit his in-laws for the holidays, took the delay in stride.

"We arrived, and that's all that counts," he said. "I'm happy to be here."

More on this story from MyFoxNY.com.