If you read the comments the police were already on the scene. The accident happened in front of the police station, and they left when they were instructed to do so due to the chemical leak. The truck was stuck (probably bottomed out) on the tracks. Truck driver was not in the truck. It was the train crew that were injured. Thank god they are alive. Hopefully they recover quickly.
You can see the hopper cars visible at 00:30 sec derail a few seconds later as the tanker cars just before them on the train derail out of sight to the left.
None of US were there so none of US should say anything about it because we don't know ALL the facts. And the video can't by itself show ALL the facts. It could be used by the NTSB investigators, but they would Never assume it has all the facts either.
If I saw a train wreck like that, I wouldn't be hanging around running video camera. With the likely possibility of chemical or fuel leaks, I would be moving away real fast.
You can actually see the first locomotive tipping over (at 0:15) before the plume of smoke obstructs the second loco and tank cars. I didn't even realize it was a derail first time watching until they went to turn around and you see the cars derailed.