2 Border Tracks???

Had to do some work in the Riverland yesterday so decided to stay overnight and "take the long way home" (to Adelaide) down the top part of the Border Track from just out of Renmark to Pinnarro.

Found a track running South from the Mildura Rd smack on the Vic border no worries. The track was basically 2 wheel ruts and pretty overgrown. Often I had to stop and clear the way, break off protruding branches etc to save the duco.

After a while I noticed that about 20 metres to my left (East) there was another track running parallel. From what I could see it looked much more substantial than the track I was on. I thought that it must be something to do with the Murray - Sunset National Park.

Quite a bit further on there was a cross road/track and I decided to pop over and check out this other track. I was very surprised to see it clearly signposted "Border Track". What was I on? I was clearly closer to the border (running along the fence). Was I on an old Border Track and there is now a new one? Then I had the comical thought that the Border Track was now a Dual Carriageway! (then I realised if that was the case I had been driving on the wrong side of the road)

I took off down this new track which was much wider and more like a graded track although quite sandy in places. What interested me was how different the 2 tracks were despite being only a stones throw apart. The 1st was quite firm but overgrown whilst the 2nd was quite sanding with some small dunes developing on some of the crests, obviously due to the fact that a wider area had been cleared and exposed to the wind etc.

Anyway, both were interesting in their own way. I would be interested if anyone knows any more about why there are 2 tracks?

Thanks

Trevor