Thank you Jrg1 and Spitfire,
Cor, I don't know where to start, I'll attempt to describe my weathering techniques but they really do vary widely.
For the above wagon, I painted it in the base colours which in this case were red, light brown and black I then added a dirty brown wash to the body, and when dry took that wash off, after that I apply a dirty black wash which darkens the red and brown creating a grimy feel in the corners of the strapping, once I'm happy with the colour that the body is, I then move onto the chassis and to do this I apply again a dirty black wash to the black and when that is drying add rust weathering powders, and a touch of rust coloured paint in some places, then once that is dry I add a dry brushing of track dirt brown and on top of that some smoke weathering powders to pull it all together and dull it all down, I also add the tack dirt colour to the lower areas of the body and then dry brush a black enamel paint and powders to simulate coal dust etc, once I'm happy with the outside I move onto the inside of the wagon and I've done something different this time, instead of applying a wash I've just applied black weathering powders to a nearly dry base coat and I personally think this gives a far better textured result, when that is done I then use a fine brush and pick out all the straps on the inside and out with some rust paint. I also add the replacement planks at this stage to give a more realistic look and I do this by using a light wood colour and with some powders to stimulate light dirt on them. Now we are nearly finished, the only thing to do is add rust powders to the buffers followed by satin black paint on the axle boxes and buffer centres.
I really hope the above makes sense as I'm pretty rubbish when it comes to describing things, if you really want I can make a YouTube video putting everything above into effect.
Thanks
Nelson
Edit: I forgot to mention that I paint the lettering after the base coat of red dries