The US president tweeted out his response to the Amtrak crash, which killed at least three people after the train plummeted from a bridge into a busy highway.
He said: “The train accident that just occurred in DuPont, WA shows more than ever why our soon to be submitted infrastructure plan must be approved quickly.”
The US had spent too much money in the Middle East while ailing to invest in infrastructure at home, he said, later repeating the comments in person.
His tweets continued: “Seven trillion dollars spent in the Middle East while our roads, bridges, tunnels, railways (and more) crumble! Not for long!”
The source for the $7trillion figure is unclear. The cost of American wars in the Middle East is estimated at between $3trillion to $6 trillion, according to Harvard and Brown Universities.
Mr Trump followed his initial tweet with one of thanks to first responders, and offering his thoughts and prayers to those involved.
At least three people died and 100 hospitalised following the derailment.
Several vehicles were hit by the train as it plummeted from a bridge into a busy highway, but remarkably no motorists were killed. It was found to be travelling at 81.1mph in a 30mph zone.
A state of emergency was declared in Washington following the crash near the town of DuPont, close to state capital Seattle.
Mr Trump doubled down on his infrastructure comments later in the day, saying the derailment was “all the more reason why we must start immediately fixing the infrastructure of the United States”.
He had pledged a $1trillion infrastructure plan as a presidential candidate.
Mr Trump then included a $1trillion infrastructure investment in his 2018 budget, calling for $200bn in spending.
However the plan limited money to build new or expand existing lines and slashed subsidies for rural infrastructure.
This would cut Amtrak spending by 13 percent, with deep cuts to long-distance service and construction grants.
The Trump administration’s transport budget referred to Amtrak’s long-distance service as outdated and “a vestige of when train service was the only viable transcontinental transportation option”.
It said Amtrak should focus on its service connecting New York, Washington DC and Boston, which has a repairs backlog of $28 billion.
The service in Washington State, where the crash took place, was not set to receive any further funding.