ABC News December 18, 2017

Trump touts infrastructure plan after derailment, but proposed budget would cut Amtrak funding

WATCH: Deadly train accident on new route between Seattle and Portland

Hours after the Amtrak train derailment that killed at least three people and injured around a hundred near Tacoma, Washington, today, President Trump argued that the accident highlights the need for infrastructure spending.

"The train accident that just occurred in DuPont, Wash., shows more than ever why our soon to be submitted infrastructure plan must be approved quickly. Seven trillion dollars spent in the Middle East while our roads, bridges, tunnels, railways (and more) crumble! Not for long!" he tweeted, adding his condolences for the victims several minutes later.

But the track involved in Monday's incident wasn't crumbling. In fact, the derailment followed a multimillion dollar track upgrade.

According to the Washington State Department of Transportation, the track had just been modified to accommodate passenger trains as well as freight -- and the locomotive that derailed, 501, was the very first Amtrak train to carry passengers down that new route.

Amtrak had hoped the track, which had fewer tight curves and single-track tunnels, would make the Seattle-to-Portland trip faster and more reliable.

Now, investigators are trying to determine what caused the train, carrying at least 84 passengers and crew, to hurtle off the rails and slam onto the highway below.

John Froschauer/AP
Cars from an Amtrak train that derailed spilled onto Interstate 5, Dec. 18, 2017, in DuPont, Wash. The Amtrak train making the first-ever run along a faster new route hurtled off the overpass near Tacoma.

Aside from Trump's infrastructure proposal, his budget blueprint for next year would restrict any federal funding for the Federal Transit Administration's capital investment program to already-approved transit projects.

"Future investments in new transit projects would be funded by the localities that use and benefit from these localized projects," the blueprint says.

The president has long urged that public-private partnerships pay for infrastructure upgrades, arguing that tax credits would incentive investors to spend big on new roads, bridges, and railways. That money would later be recouped through taxes on wages and contractor profits, his advisers have said.

Trump's proposed federal budget would also slash certain federal subsidies to Amtrak. The executive budget proposal "terminates support for Amtrak's long-distance train services which have long been inefficient," according to documents posted by the White House earlier this year.

The route on which 501 derailed is not classified as long-distance, Amtrak tells ABC, which means this particular train line likely would not have been impacted by these proposed cuts.

ABC News' Whitney Lloyd and Jeffrey Cook contributed to this report.