Ah I just realised I have the wrong picture! That one is from another that happened in the pilbara. No one was hurt there.
This is the one on the border:
It happened just ouside of our territory (on the WA/SA border), so not our line, but it has stopped all trains through there for a good 5 days. The pic is some 500m of wagons in about 100m of space.
And three people were hurt here - you can see the locos at the bottom of the pic on their side. These wagons contained a caustic oxidising substance and some of them landed in water, so was pretty bad situation.
The thing with derailments is that they are actually quite common, and hard to stop. It doesn't take much - a crappy wheel on a wagon might catch a bit of ballast or pass through a heat warped section of line, and then it just pops off, and turns into a disaster. Building another line wouldn't stop this sort of stuff. It's like getting a flat tyre - it happens to everyone eventually.