Painting Rusty Rails in T gauge

I've had a kick up the bum to do something to my layout as I've found out that I'm doing and exhibition in 2 weeks time apparently Aaaaahhhhhh!!!

I had started painting the rust on the rails but had only done about a third of the layout. Having this unfinished would look a bit naff, so I have to paint the rest now pronto. 

I'm using a size 0 brush with Humbrol Acrylic rust colour. The results are quite pleasing I think. The track was painted with grey and dark ink a long time ago.

The difference between unpainted and painted track.