Just had a look at the series of pics you mentioned again. If they are posted in the order taken then they are taken from a south bound train. The give away is the road train turning area down the south of Union Reef.
On Wednesday (Ghan departure day) MD3 is due into Darwin about 10 minutes before The Ghan is due to depart. If MD3 is running late (even by 10 minutes) then we are held at Union Reef for 6 hours waiting for The Ghan. That could have been the cross. This one only happens on a Wednesday and only if MD3 is late.
On Saturdays (when The Ghan runs south) there is a cross out at Union Reef with the Iron Ore train. Maybe on this day DU4 could have been running late for The Ghan to be so close to it. Usually this train is 90 minutes in front of The Ghan.
Thanks for more inside information, Wiseone.
I am in danger of getting lost in the bush here! Just to recap
1. Nightfire said that the northbound Ghan on which he arrived in Darwin on Tuesday 15th June was reported (by the onboard announcer) as following an iron ore train, which it would pass at Union Reef. This implies that the ore train was south of Union Reef. He didn't see them pass but did see the stockpiles at Union Reef.
2. The movie clips were taken by me from a southbound Ghan in May 2009. This Ghan did not pass or cross anything at Union Reef.
3. Seeing the clips, Nightfire said that his northbound Ghan ran through Union Reef on the siding and not on the main line.
4. Wiseone explained that the northbound Tuesday Ghan might run on the siding to cross the DA2 freight at Union Reef and then follow iron ore train UD3. This would explain Nightfire's experience on the northbound if the announcer had got it completely wrong, and I think is the most likely explanation. My suggestion that it followed a Muckaty ore train south of Union Reef and passed that at Union Reef seems less likely.
Wish I could come and sit at Union Reef for a while to see what goes on. Maybe next year.