This can happen and it will happen again. You need a bit of bad luck.
I ride Rails to Trails almost exclusively and they are comparatively safe compared to roads. That does not mean that there is NO chance of accidents such as:
Bikers spaced out on your side coming at you eyes wide open.
Kids.
Dogs.
Farm vehicles crossing. Cars crossing. Bikes crossing.
Giant potholes.
All kinds of animals.
Blinds curves with who knows what is in the blind spot.
Bikers with ear phones all over the trail.
That all said, I see less then 5 people and none of the above on my 46 mile ride of yesterday.
BTW, I have been on the trail you mentioned and set a personal speed record on that trail. My only problem was that I had trouble walking from going too big a gear.