This substance when mixed with water sets up like concrete (thanks to the Portland Cement) and is great for forming the ground. You have about 15 - 20 minutes to work the mixture into its rough form, then you just have to spray it with water to smooth out the top surface to the required terrain.
After this has completely dried (usually a day or two) its time to add the zip texturing which is the final dirt like layer. This is just a mixture of Plaster of Paris (finely sieved) and tempera powdered paint to the required dirt colour.
Again a light spray of water on the dried ground goop, and then using a fine sieve you cover (lightly) the ground goop with the zip texturing, then another light spray of water to set up the layers.
I also added some more static grass to some of the completed fascia areas, added some more bushes, and also finished off the raised ground area on the JL&T module.
I've also added the Tortoise Switch Machines to the staging area entrance so that I can finish off the fascia's in the L&T area.