With the disaster and death that affected so many on Monday morning after an Amtrak derailment, the search for the cause may have its roots in the past.
"Let's be clear. People are dying, they're being injured because we don't have Positive Train Control," said former Senator Barbara Boxer, a Democrat from California.
This wasn't some urgent debate this week in the Capitol.
It was October 2015 -- when Congress was debating Positive Train Control.
That system uses GPS, wireless signals, and central control to help sense trains in danger of crashing or derailing.
It was not in operation during the crash Monday because it didn't have to be.
That's because of a decision Congress made two years ago.
"We need to have an opportunity for that implementation to occur over a slightly longer period of time than what was originally planned," said Senator Jerry Moran (R) - Kansas.
We found that the original deadline for PTC installation was the end of 2015. At the time, the rail industry called the demand "absolutely impossible" and could cause "massive disruption." Amtrak and others threatened a shutdown of the rails.
"These disruptions would have caused cascading and devastating effects for nearly every sector of the economy in every region of the country," said Senator John Thune (R) - South Dakota.
The House passed the 2018 deadline extension unanimously and the Senate offered little resistance.
Some Democrats did raise red flags -- and chilling warnings of what ended up happening.
"It is an insult to the families who have lost loved ones to let the rail lobby slip a multi-year positive train control delay into a three-week extension," Boxer said.
She wanted only a one year delay but her amendment was shot down.
"The rail industry has purposefully dragged its feet in meeting safety requirements and now Congress is quietly aiding them further," Boxer said.
The bill eventually passed and was signed by President Obama.
The rail lobby said it wanted more funding from the feds and time.
In this case, we found that the Sound Transit rails and some cars had PTC, but the control center wasn't ready to go.
Because it didn't have to be.
"They sought it. They won it, with a threat to shutdown railroad service everywhere in the country. An unacceptable outcome," said Senator Richard Blumenthal (D)-Connecticut.
The current deadline for installation is 2018, but some rail lines could get waivers to avoid having PTC in place by 2020.