Colorwise I suggest either Vallejo 71.078 or Modelflex 16-10. For brushable try Tru-color 841. Their airbrush color is 069. I use Tru-paints extensively and like it very much.
I recently picked up a bottle of Polyscale Reefer Yellow for the grab irons on my BNSF SD75M. This is hands down the best Yellow paint I've ever used. I know that poly scale is not longer made, so whats the best alternative for this bottle of paint?