Steve Dipaola / Reuters The scene where an Amtrak passenger train derailed on a bridge in Washington Monday.

WASHINGTON ― Congress delayed the implementation of an advanced safeguard that could help prevent railroad accidents like the one in Washington state Monday.

At least three people were killed and dozens more were injured after an Amtrak passenger train heading from Seattle to Portland, Oregon, plunged off an interstate highway overpass, law enforcement officials said.

Amtrak officials said a new safety mechanism called “positive train control” was not activated at the time of the derailment. The train was traveling on an inaugural run of a high-speed service route.

The Amtrak Cascades 501 service was approved to reach speeds of up to 79 mph, but investigators late Monday said that that the train was traveling 80 mph in a 30 mph zone at the time of the incident. Officials said it was “too early” to tell why the train was going that fast.

Positive train control is a system meant to automatically stop trains before certain accidents happen, like train-to-train collisions and derailments caused by excessive speed. After a 2008 crash in California, a new law required trains across the country to install the technology by the end of 2015, the Hill reported.

But as the deadline approached, Congress extended it until the end of 2018, after receiving complaints from freight and commuter railroad companies about the difficulty of converting to the new system. The extension was part of a five-year highway bill compromise between the House and Senate that President Barack Obama signed into law.

Sen. Richard Blumenthal (D-Conn.), who warned about delaying positive train control at the time, tweeted Monday that the technology “must be implemented immediately.”

Technology like Positive Train Control must be implemented immediately to prevent trains from speeding and flying off rails. Statutory deadline is 2018 – no excuses. — Richard Blumenthal (@SenBlumenthal) December 18, 2017

Other lawmakers said they’d like to see the results of the investigation before drawing conclusions.

“We don’t know that it could have saved lives,” Rep. Denny Heck (D-Wash.), who represents the district where the Monday derailment occurred, told CNN of the technology after the crash. “But it was a disappointment that we’re not further along in implementation and installing PTC in trains throughout America.”

“We can’t jump to conclusions,” Heck further warned.

The National Transportation Safety Board is conducting an investigation into the accident, but it may take months before it is completed.

The absence of positive train control was a contributing factor to a deadly passenger train derailment in Philadelphia in 2015, according to the safety board. In that incident, an Amtrak engineer became distracted and accelerated to more than twice the speed limit as he entered a curve.

President Donald Trump initially addressed the deadly derailment on Twitter by making the case for an overhaul of the nation’s crumbling infrastructure system via a plan he is expected to soon unveil. The incident in Washington, however, occurred on a brand new service line.

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. Seven trillion dollars spent in the Middle East while our roads, bridges, tunnels, railways (and more) crumble! Not for long! — Donald J. Trump (@realDonaldTrump) December 18, 2017