Did they ever interview the engineer?

with a max speed of 30mph.

Odd, really.

and they will report as they have conclusive information. Here is their preliminary report: https://www.ntsb.gov/investigations/Pages/RRD18MR001.aspx and https://www.ntsb.gov/investigations/AccidentReports/Pages/RRD18MR001-prelim.aspx

However, the NTSB is quite another matter.

for the curve.

..before the accident. I'm sure they are still looking into it.

He prevented all the plane crashes. Must have forgot about the trains

At least that's true for aviation accidents. This one might not take as long but there's a process they use and it's definitely not for those who need instant answers. Here is their preliminary report: https://www.ntsb.gov/investigations/Pages/RRD18MR001.aspx and https://www.ntsb.gov/investigations/AccidentReports/Pages/RRD18MR001-prelim.aspx

mile markers as well as having a Trainee in the Cab as a distraction .

How many weeks should it stay in the news?

Much too soon.

Here, take a look at these FAA reports:

https://www.ntsb.gov/investigations/AccidentReports/Pages/aviation.aspx

AAR1702 Collision with Terrain Promech Air, Inc. de Havilland DHC-3, N270PA, Ketchikan, Alaska, June 25, 2015
Final report date 4/25/2017

AAR1701 ​Aircraft Accident Report: Loss of Control at Takeoff Air Methods Corporation Airbus Helicopters AS350 B3e, N390LG 7/3/2015
Final report date 3/28/2017

Okay, now these are fairly mundane incidents involving a small plane that crashed into the ground, and a helicopter that lost control taking off back in 2015. The final reports were issued almost two years later.

To really go over ALL of the data on something like this requires a lot of time and expertise, even if there is an "obvious" answer. It is avoiding the trap of the "obvious" and making sure that all possible contributors have been analyzed, which makes these reports take time. They do a full reconstruction of everything that happened, and a full analysis of every scrap recovered to square it with whatever other data they have.

What happened?

The train was going too fast around a corner. It derailed.

If you want to know why the train was going to fast around that corner, that's going to take time, and the answers have to be as correct as humanly possible.

The operation of every signal light and system on and off that train is going to be examined. The inspection reports on every piece of that equipment going back years is going to be examined. They are going to know the location of every passenger and determine how every injury occurred. They are going to know what the guy in seat 10A had for breakfast. Everything.

Those things make interesting reads, both in content and in the writing style. There's one on a sightseeing heli that went down in the Grand Canyon a while ago that is absolutely gripping. It's like a novel written by an alien species. Bottom line - the pilot was something of a nutjob - but that's the nugget inside a tremendous wealth of information.

Honestly and seriously, take a look at the plane that crashed in Alaska. That report is 75 pages long. After reading the introduction, you can't put it down:

Abstract:

This report discusses the June 25, 2015, accident in which a turbine-powered, float-equipped de Havilland DHC-3 airplane, N270PA, operated by Promech Air, Inc., collided with mountainous, tree-covered terrain about 24 miles east-northeast of Ketchikan, Alaska. The commercial pilot and eight passengers sustained fatal injuries, and the airplane was destroyed. Safety issues discussed in this report relate to the need for training program improvements for Ketchikan air tour operators that address pilot human factors issues, such as assessment of safe weather conditions, recognition of potentially hazardous local weather patterns, and operational influences on decision-making; the need for collaboration among Ketchikan air tour operators to identify and mitigate operational hazards through analysis of automatic dependent surveillance-broadcast data; the lack of conservative weather minimums for Ketchikan air tour operators; the lack of defined curriculum segments for controlled flight into terrain-avoidance training for all 14 Code of Federal Regulations
Part 135 operators; nuisance alerts from the Class B terrain awareness and warning system during tour operations; the limitations of older software and terrain database versions for the legacy Chelton Flight Systems FlightLogic electronic flight instrument system; the lack of minimum training requirements for operational control personnel and the lack of guidance for Federal Aviation Administration inspectors for performing oversight of operational control training programs; the need for cruise industry awareness of schedule pressures associated with air tours sold as shore excursions; the lack of a requirement for a safety management system for Part 135 operators; and the lack of a crash-resistant flight recorder system.

-------

I like this part of "what happened?"

the need for cruise industry awareness of schedule pressures associated with air tours sold as shore excursions