Concours77 - I was agreeing it looks sort of like the forward vibration isolator. They can get into the cowl from several directions. From the maintenance images I've seen, and from the manuals, the sides are what they always open up. Going further might require just some more quick screws, but the garden variety maintenance always shows the sides up. I've never seen the forward cowl off an engine that's sitting on its mounts.
I am strongly persuaded that the prop hits on the railroad track were from prop three. There is a bunch of circumstantial evidence that four was torn off at the railroad, and what I'm looking for now is the smoking gun. Evidence includes the missing engine puzzle referenced earlier, the amount of damage to the tracks which looks to my novice eye like more than a wingtip would do, the large object on the track, etc.
G0ULI - I frankly don't recall whether the engine four or the turning radius epiphany came to me first. Evidence for the 35 degree bank is in the Lockheed map of the path, in my attempts to reach anything higher that were fruitless with respect to that location on the field, and in the forward sliding scenario as opposed to the impossible CAB cartwheel. Finding engine four somewhere else, and finding that prop four made the divots, doesn't change the bank angle. But finding that engine four was torn off at the track would certainly be the kiss of death to the high bank.
The best evidence against the large object being wingtip is that it would have been featured in the papers. They went with the most spectacular bit they had, and that was something the size of a crumpled rug. If the wingtip were left on the track, a team of half a dozen guys could move it to the idle track and the RR would be back in business. If the engine were left on the track, the RR would have called in a crane and flatbed and loaded it up and rolled it away, leaving small stuff for the photog to find.