Now that I'm looking at the pictures on another monitor the rust is wayyyyy too bright, it's a heaps more toned down in reality.
Anyway since there have been some questions here's what I did:
Being an OOB build I used the vinyl kit tracks and primed them with some flat grey from a spray can. Then a base color of metallic silver mixed with flat black (more black than silver). Below is a picture of the tracks after that paint and some very careful application of rust pigments. On that white palette you can also see the mess of different colors I used:

Then I tried some light rust pigments but they ended up too bright and discrete so I washed the tracks with burnt umber oil paint and at some point I added some pigments to the mix. This worked rather well for the rust which was still too obvious. In the end I had a rusty and muddy "sludge" of colour which I applied like a wash.
After the wash had dried overnight I toned down the rust with some dust pigments (Mig Europe Dust) and finally rubbed the raised bits with a pencil to get that attrition sheen. I reckon a rather soft pencil or a block of graphite would work the best. I just used the first pencil I found which happened to be HB2 softness.
I got most of the ideas from following the excellent advice in
this thread