A Washington state politician is questioning whether Amtrak had sufficient safety measures in place before Monday's deadly derailment.

"It's going to call into question the overall safety culture that Amtrak may be lacking," Washington House of Representatives member Dick Muri told China Daily.

An Amtrak 501 Cascade train, with 78 passengers and five crew members, derailed on an overpass early on Monday on Interstate Highway 5 in Pierce County, Washington, with some of its 14 cars crumpling and plunging onto the road.

Three people died in the crash and more than 70 were injured. As of Tuesday, 35 people were still hospitalized, including 21 in critical or serious condition.

Several people were injured on the highway, though no fatalities were reported.

"The train cars will be removed (from the highway) by the end of the day," said Mike Courts, mayor of DuPont, the small town in which the train derailed. He said they were aiming to clear the highway before a snowfall.

Muri, a Republican who represents the 28th District, added: "We have been questioning for the last couple of years, many years, about the whole idea of high-speed train coming to our land here.… This is way above our level. It is a federal issue when you talk about train safety. Hopefully, our concerns have been voiced at the highest level."

Investigators also are looking into whether the train's engineer was distracted by the presence of an employee-in-training next to him in the locomotive, a federal official said on Tuesday.

The official, who was not authorized to discuss the matter publicly and spoke on condition of anonymity, said investigators want to know whether the engineer lost "situational awareness" because of the second person in the cab.

Preliminary information also indicated that the emergency brake went off automatically and was not manually activated by the engineer, National Transportation Safety Board member Bella Dinh-Zarr said.

The train was making the inaugural run along a faster route that was created by refurbishing freight tracks alongside I-5. The 24-kilometer, $180.7 million project was aimed at speeding up service by bypassing a route with a number of curves, single-track tunnels and freight traffic.

At a meeting on Dec 4 in Lakewood, Washington, southwest of Tacoma, Mayor Don Anderson said it was only a matter of time before the Amtrak train would be involved in a deadly accident.

"It's virtually inevitable that someone is going to get killed that wouldn't be killed otherwise," Anderson said then. "This is unacceptable."

The city of Lakewood sued the Washington state Department of Transportation in 2013, looking to stop the project, arguing it did not have a sufficient environmental review, The Seattle Times reported. The city lost partly because the law prevents cities and towns from regulating rail lines.

Dinh-Zarr confirmed at a news conference late on Monday that the data recorder in the train's rear locomotive showed the train was traveling at about three times the speed limit (48 km/h) when it derailed.

She said it was too early to determine why the train was going so fast.

The Associated Press contributed to this story.