One year ago, at 9:21 p.m., Amtrak Train 188 derailed at Frankford Curve, killing eight and changing life for hundreds.

Since then, the May 12, 2015, crash has dominated conversation in the rail industry. It highlighted the value of an automatic braking system that authorities said would have prevented the crash, and provided new urgency for efforts to improve technology, safety, and funding for the nation's railroads.

"We talk about the Amtrak crash all the time," said Sarah Feinberg, the Federal Railroad Administration's administrator. "I think it's important for people to remember this is the most deadly rail accident we've had in a very long time."

Yet crucial questions remain unanswered, specifically what role the engineer, Brandon Bostian, played in the crash.

The train derailed while traveling about 106 mph, more than 50 mph faster than the speed limit for that turn. Investigators from the National Transportation Safety Board ruled out mechanical, signal, or track failures as causes and have focused on human error. Evidence showed that Bostian accelerated the train until moments before the crash, when he hit the emergency brake too late.

More clarity may come Tuesday, when the NTSB is expected to meet in Washington to determine the cause of the crash. Meanwhile, according to Amtrak, Bostian remains suspended.

Bostian's lawyer, Robert Goggin, did not return calls for comment.

Amtrak's president and CEO, Joseph Boardman, declined to be interviewed, but released a statement. "This was a tragic event and we take full responsibility for our role in the derailment and work every day to strengthen rail safety," he said.

About 119 lawsuits have been filed in the case, and Amtrak so far has settled 19 claims, for amounts of less than $50,000.

The amount of money Amtrak can pay out in claims is limited by law to $295 million. Some of the lawyers involved in the case say that there's a good chance claims will exceed that, and that passengers will be competing among themselves for compensation.

Investigators have said that PTC, or positive train control, an automatic braking system that slows or stops a train to prevent an accident if an engineer fails to, would have prevented the derailment if it had been present on Frankford Curve.

Amtrak has since installed PTC throughout its Northeast Corridor on rail it owns, but away from the Northeastern U.S. much of Amtrak's service runs on track owned by private freight companies, which have not installed PTC, Feinberg said. Congress delayed a 2015 deadline for PTC installation to 2018, and Feinberg wants rail companies to install the system before that.

"PTC just has to be a huge priority and needs to be implemented as soon as possible," she said.

On Wednesday, U.S. Sen. Bob Casey Jr. (D., Pa.) urged Congress to fund Amtrak at the $1.9 billion amount the Obama administration has requested. Congress is considering a lower number, $1.42 billion. The White House request is essential, Casey said, to help pay for PTC and other infrastructure improvements for rail agencies.

"I'm certainly willing to work with anyone to knock down those obstacles," Casey said.

More money for rail is the single biggest thing that can improve train travel safety, said Jim Mathews, CEO of the National Association of Railroad Passengers.

"We are so far behind as a nation on infrastructure investments," he said. "It's almost impossible without a moon shot to address everything quickly enough."

He noted, though, that fewer passenger-train accidents were reported in 2015 than in the last few years. Amtrak transports almost 31 million people each year on 21,300 miles of rail, and perennially has financial troubles. Just three months ago Boardman requested budget cuts from all departments to offset shrinking passenger revenue.

Technology could have helped determine why the train sped into the turn. Bostian has said he doesn't remember key details from the derailment. Inward-facing cameras might have made it easier to learn, and the FRA is in the process of making a rule that would lead to those cameras' installation.

Also being looked at is how rail cars withstand crashes, said Feinberg. In the Train 188 crash, some passengers were ejected through windows, which are typically weak points on trains. Part of the challenge is the multiple roles windows play. They should be difficult to shatter but easy to remove in case of an emergency.

The FRA, Feinberg said, is conducting an engineering study to determine how to make windows less of a liability.

The cars involved in the crash were about 40 years old, and one rail expert noted that newer trains can be designed with crumple zones similar to a car's to absorb the impact of a crash, said Ronald Mayville, an expert in train crashworthiness with the Boston engineering firm Simpson Gumpertz & Heger. Still, a train's mass limits how much protection can be offered in a high-speed crash, he said. Sheer luck may have kept more people from dying.

"When you start getting at a very high speed," he said, "all bets are off."