I thought it might be useful to put up a step-by-step of how I weather my next loco - so here it is, complete with cruel close ups! Starting with a fresh Farish class 20, with bufferbeam detailing added on one end, coupling pocket removed from the bogie, DCC fitted and run in.

Here's what you need for the first stage. Some black and burnt umber oil paints (I bought a pack in the works for a couple of quid years ago), some thinners, a pallet (old jam jar lid) and a cradle for your loco - mine is made from a kitchen scouring pad chopped in half!

Make up a wash of grimy black (avoid using pure black) adding thinners until itsjust a bit thinner than milk. Paint this onto the body of the loco, adding more thinner and letting the capillary action fill the details where needed. Don't worry about being too neat, you can work with the oil paints for ages, using a brush dipped in thinner or a cotton bud to remove any areas you need to.

Let the washes dry and once you are happy, you can protect them with a coat of varnish - I swear by Citadel Purity Seal spray, its the secret weapon! 3 light passes on each surface is all you need.

It'll take the shine from the factory finish and also lightly mist up any clear parts - this can be a bonus in N gauge, but any you want to remove can be done with a cotton bud dipped in thinners. You could also use Maskol or similar before spraying.

Once the varnish has hardened, it's time to add some powders. I use Humbrol dark earth mixed with a bit of Forge World's soot black, but most brands will carry some similar tones. Experiment to find a tone you like, mixing them adds a bit of variety. I brush these on with a square brush, using a cotton bud or the mark 1 finger to remove any I feel needs to come off. Add to taste - add a bit, remove some, add a bit more, remove some etc. I use the soot colour need on the roof, especially around the exhaust ports.

And here it is - compared with the first image, I think it looks a lot better for a small bit of effort. Still a few details to do - I'll pick out the buffer beam pipes a bit, rub some ground up pencil graphite onto the bufferheads and paint the shanks silver. I'll also remove the varnish from the headcode box, but I tend to leave it on the windows - it looks better in real life than the photos, I promise!

So there you go - what I have found works for me. I'm not pretending to be an expert, but hopefully it'll inspire someone to have a go!