So I have had a go at creating some BNSF Santa Fe Warbonnets "pink boats" Dash9-44CWs.
Basically I started with two Kato Dash9-44CWs.
Firstly I created a wash of "pink" using Humbrol paints, with red and white and a touch of purple.
Over washing on the lines etc.
Gave it a day to dry, then used a cotton bud soaked with mineral turpentine, and rubbed the bud in areas, one to make clear lines around the "Santa Fe" letters, the other is to create stippling of the paint.
The grilles were washed with a mix of Humbrol black and gunge.
The rust spots on the roof was again a mix of humbrol yellow red and gray.
then I added a wash of dark orange around the edges of the dark rust spots.
The exhaust stains are Tru Color Grime.
And the road grime is a concoction.
Here is the finished product