Thank you Kirley and burnthebox, I appreciate it.
The dapol wagon was weathered in a number of steps that all lead up to the desired finish. Here's how I did it.
I painted the underframe in a dark grey instead of the usual black, then added humbrol rust weathering powders and gloss black paint for oil spills,
Then for the body I used railmatch enamel light rust paint on a cotton ear ear to dab the rust on the end plates and frames to give a representation of rust showing through, then with humbrol smoke weathering powders, brush them along the edges and into the spaces between the planks, then add a small amount of humbrol rust weathering powder again to the metal parts. And keep adding different layers and quantities to suit you, and that's how I did it, doesn't take to long and the powders don't need a cover of varnish because they are well worked into the paint that they will stay on fine on their own.
Hope this was of some help?
Thanks
Nelson