I have run a similar size cable crane a little bit, and a hydraulic one a lot. That is not a move any crane operator would likely want to have happen, because when things swing that far, imagine the pendulum affect of the box car now coming back toward the crane and the dock. That kind of unstable move if it was a swing to the side could even tip the crane over when the inertia of the swinging car is arrested by the hoist line. My guess is the photographer caught a rare event that was not going as planned. I'd give a nickle to see several more sequential shots in the next few seconds.