Washington Senator Maria Cantwell has asked for a hearing on Amtrak safety standards following this week's deadly derailment in DuPont.

Related: Family of critically injured Amtrak passenger wants answers

“Our heart breaks for the families and the individuals impacted by this unbelievably tragic accident,” Cantwell told KING 5 on Thursday. “What we want to do now at the federal level is make sure we're asking all the questions about Amtrak operations and current safety standards and also what will it take to make sure we're making improvements that will help reduce human error.”

Cantwell wrote the Chairman of the Senate Commerce, Science and Transportation Committee to request an oversight hearing on safety standards and training procedures when lawmakers return in January.

Related: Cantwell letter to Commerce Committee Chair

Separately, 15 U.S. Senators including Washington's have written to the U.S. Department of Transportation to ask the agency what's being done to make sure railroads comply with the new safety measure, Positive Train Control, designed to stop trains from colliding and speeding.

Congress mandated PTC following the 2008 crash in Chatsworth, Calif. that killed 25 people. However, in 2015, Congress delayed the deadline for implementation until December 2018, after railroads raised concern about the cost of installing the safety upgrade and lobbied for more time.

“We certainly pushed to have it implemented sooner,” Cantwell said. “The delay was stuck into a larger piece of legislation that passed. I think many of my colleagues would rather instead implemented it sooner, but regardless of that, we want to make sure that every day Amtrak operates safely.”

“We'll have this hearing and get an update on the implementation and time frame, but regardless of that, we want safety every day under the Amtrak current operations,” Cantwell continued.

Cantwell says she plans to visit DuPoint next week and talk to all agencies involved in the investigation, as well as community members in Lakewood who raised concern about the new rail line before Monday's crash.

On Thursday, WSDOT Director Ron Pate told elected officials that Amtrak trains will not return to Point Defiance Bypass until the Positive Train Control system is operational.

The new PTC technology is required for all “mainline” railroad tracks, as defined by the Federal Railroad Administration.

NBC News reports only 37 percent of freight lines have installed PTC, so far, and only 23 percent of passenger lines.

Related: Status on PTC implementation by railroad

Among the questions Senators are now asking in their letter to DOT:

1. Based on the reports and information provided to you by railroads, and your knowledge of efforts necessary to complete PTC implementation, what railroads do you anticipate will have fully implemented PTC by the end of 2018?

2. What railroads do you anticipate will fail to implement PTC by 2018?

3. What is your plan to impose fines and penalties for railroads that fail to comply with the law?

4. Can you confirm that you will be vigorous in enforcing the deadline, imposing strong fines and penalties, where necessary, on railroads that fail to meet the deadline?

5. How are you communicating your enforcement plans to the industry?

6. What steps are you taking to implement other provisions of law and safety requirements, such as requirements from the 2015 surface transportation bill, known as the FAST Act, that passenger and commuter railroads complete a speed-limit action plan (section 11406) to prevent over-speed accidents into curves and commuter railroads improve inspection practices (section 11409)?

7. What level of funding will be included in the President's yet-to-be-released infrastructure proposal to expedite PTC implementation and advance other rail safety efforts?

8. What steps is DOT taking to approve and expedite the use of federal funds and grants by recipients for the implementation of PTC?