My point is, the freight train would not have been going 50 mph, but more likely 35 mph if not slower if at an earlier signal, the train had been slowed by PTC. Therefore, at the stop signal when PTC would have applied the brakes, the freight train would have stopped much sooner.
It's quite possible that PTC could have averted the collision entirely, or at least rendered it less severe. Had Train 413 been moving at 35 mph instead of 60 mph in the double-tracked section, it may have reached the single track after VIA 4 had already passed - even if Train 413 had not been stopped by that point.
In the accident that actually happen, the freight train was going 50 mph and never slowed.
However, keep in mind that this was 1986. PTC as we presently know it did not exist - I don't think the term "Positive Train Control" had even been coined until a 1994 FRA report.
It wasn't till after I got to work and was having an argument with the cab signals on my locomotive that I realized that point about PTC, and that makes that portion of my post erroneous and moot (went back to erase that portion). But it does bring up the point that cab signals....even cab signals without speed control protection in this case...may have prevented the accident.
In the area I work, we have lines where there is cab signal territory with an overlaid speed enforcement. In the case of a code change causing the cabs to drop to a more restrictive signal, the engineer not only has to acknowledge the change, but has to reduce the train speed within a certain time dictated by the aspect, or get a penalty brake application that stops the train.
I also work over some cab signal territory without speed enforcement. In a case like that, in theory, an engineer can acknowledge a cab signal change and keep going at full speed. However, even with that system, if a code change is not acknowledged, a penalty brake application will occur.
In the case of Train 413, if even cab signals with no speed enforcement was in place, and assuming the head-end crew was already incapacitated when passing the distant signal, the unacknowledged cab signal change would have initiated a penalty brake application and stopped the train.
So many "what-ifs" that nobody can do a thing about now.....