So now it shows that he was failing/or couldn't obey a State traffic STOP signal, at a gated/flashing RR crossing ... and/or was driving too fast to stop ... unless the truck had faulty brakes.
The driver had an unobstructed view of the approaching train, as the tracks were on an obtuse angle to his FOV ... It wasn't like the train snuck up on him from behind. Google Earth shows that there was in excess of 1/8 mile of straight road as you round a huge sweeping curve, with pavement RR markings 750 feet from the crossing. I am presuming that the accident happened in broad daylight and in clear weather.
I see you're stepping back off the edge, who cares what Google Earth shows, he wasn't driving looking at a map of Google Earth and yes you are presuming quite a bit.
Have you ever dealt with extreme glare on a laminated windshield in the desert? Do you have personal experience in stopping a tractor pulling two trailers on dry pavement traveling 80 ft./s? Is your 750 feet from the crossing something you also looked up in Google Earth, or have you actually measured it in real life? Have you ever tried to see those pavement markings dealing with extreme glare on a laminated windshield in the desert?
I could pose counter questions to you all day long that would be just as valid as your presumptions. From where you're sitting in the comfort of your own home looking through Google Earth it all seems cut and dried in your mind.
But I can tell you as someone who has had personal experience with the West Coast Amtrak moving 70 to 80 miles an hour across an unguarded crossing and I know for fact he did not hit his horn until after he was through the crossing, sitting as high as he was he could've easily saw my vehicle approaching the crossing over the vineyards but yet he didn't see fit to blow the horn. Now of course I didn't see him because the track was fairly obscured by vineyards on each side of the road, but I came within probably 2 feet of being roadkill on the front of a eastbound Amtrak.
So not everything is as cut and dried as you would like to think, just because they tested the circuitry on the signals doesn't mean the driver could see them possibly due to sunlight glaring off the windshield in the desert for example. We don't know whether the Amtrak tried to brake prior or whether or not he was using his horn before he got to the crossing. We just don't know now do we?
So until the NTSB makes an official determination as to the cause, speculation and presumption is really just that.