So far so good, but the model is looking a bit tidy for an industrial site, so time to get messy. First up a dirty wash of acrylic paint over the ballast, varying the colour to give oily patches in front of the engine shed. In this picture the track on the nearside of the brush has been dirtied, that beyond is yet to be done, the effect is subtle but worth it.
However photos of the Thakeham site show, unsurprisingly, a lot of sand. Two colours of sand in fact as the light and red sands were used to vary the colour of the concrete products. I found plenty of fine light sand in the kids sand-pit, and a friend gave me a jar of brick dust which is ideal for fine red sand. This was applied liberally but with thought - mixed in places, but with one colour dominating in others, such as around the near hopper which contains light sand.
At the other end of the line the red sand dominates around this end of the tipping shed. The track is part-buried in places and only under a light dusting of sand in others, while the paved area just has patchy areas. The photo above also shows the moss growth on the asbestos roof.