Only hours after a power outage in Atlanta paralyzed the world's busiest airport, a major train crash in Washington state on Monday raised fresh questions about America's aging infrastructure.

Multiple people were killed when an Amtrak passenger train derailed early Monday near the city of Tacoma, sending cars over a bridge and reviving a pledge from President Donald Trump to modernize key US facilities.

The crash is "all the more reason why we must start immediately fixing the infrastructure of the United States," President Donald Trump said Monday in an address on national security.

In Atlanta, hundreds of additional flights were canceled Monday even though power was restored to the hectic hub after an 11-hour outage Sunday.

Georgia Power said Monday it was still investigating the "very rare" disruption, which it believes may have been caused by a gear failure in an underground electrical facility that caused a fire.

"This is a symbol of a deeper malaise in American society that you simply have not for many, many years spent enough money on the basic infrastructure of the country," said Jacob Kirkegaard, a senior fellow at the Peterson Institute for International Economics.

"It is illustrating an accelerating decline of large public infrastructure in the US: highways, bridges, airports, tunnels, harbors, railways... which have not seen enough investments for decades," Kirkegaard added.

The shortcomings of the crumbling state of US infrastructure go well beyond the double debacle of the last 48 hours. Over the years the country has seen failing bridges, obsolete water treatment systems, other deadly train crashes and an erosion of major subway systems in New York and Washington.

Since 1998, the American Society of Civil Engineers has graded US systems a "D," a nearly failing mark on a scale of "A" to "F."

And the International Monetary Fund for over a decade has urged increased spending on key infrastructure as a means to create jobs, and boost the economy's productive capacity.

- Campaign issue -

Trump decried the state of American roads, airports and bridges during his presidential campaign.

"We are going to fix our inner cities and rebuild our highways, bridges, tunnels, airports, schools, hospitals," Trump said during his victory speech in November 2016.

"We're going to rebuild our infrastructure, which will become, by the way, second to none. And we will put millions of our people to work as we rebuild it."

US media have reported that Trump may finally unveil a long-awaited infrastructure plan early next year. The issue had been seen as a priority for former White House advisor Steve Bannon, who stepped down in August, but there has been little concrete activity since.

Kirkegaard is skeptical Trump will follow through, in part because of the effect of the massive tax cut plan that he and congressional Republicans have prioritized. The bill is near passage but does not include infrastructure funding. "What has happened since January? Nothing."

Administration officials have looked at using tax credits as an incentive for private investments in infrastructure. But many experts are skeptical such an idea will work.

The ASCE warns that airport infrastructure is not keeping pace with rising customer use, and sees a funding gap of $42 billion over the next decade.

The group warned that 24 of the top 30 major US airports may soon experience "Thanksgiving-peak traffic volume" -- a US holiday known as a peak travel occasion -- at least one day every week.

And over 40 percent of buses and 25 percent of rail transit assets are in "marginal or poor condition," the group adds.

"Deteriorating infrastructure is impeding our ability to compete in the thriving global economy, and improvements are necessary to ensure our country is built for the future," ASCE said.