Quote:

what was that crew doing that they did not see signals or oncomming traffic with thier pair of mark 1 eyeballs

Since they apparently just tied onto the cars they were picking up, and wouldn't expect to be be going anywhere until the opposing train cleared, how about this:

Conductor walking back releasing handbrakes and/or getting ready to walk an air test, while the hoghead visits the can down in the nose?

From Google Earth it looks like a little under 0.5% downgrade toward the switch, so if the independent was accidentally kicked off on the way to the can (there's your crew error/failure) and the train was charging/releasing, it would slowly start to roll toward the fouling point.

A conductor halfway back along the cut would just see the slack starting to roll in as the cars released, and wouldn't be alarmed until they had obviously rolled more than one would expect from slack alone.

I'm not saying this is what happened, but something along this line is much more likely than the idea that a pair of those "no good" railroaders were sitting in the cab, and blatantly chose to initiate movement from a stop (starting just a few hundred feet from the impact point?), proceed past a red signal and into the side of the passing train.

An uncontrolled movement such as this would be the only failure of the crew in this scenario. There would be no smoking gun regarding PTC in "switching mode", or lack of vigilance regarding signals, because they wouldn't have even been ready, or intending, to move, and may not have even realized they were moving.

This would also be one of the many types of scenarios where PTC doesn't work, even if it's cut-in.