As an interim step I decided to use Austrains VPCX's for delivering concrete to the industrial siding for Adelaide Brighton Cement.
So here is my first attempt in weathering a concrete wagon, first start with a diluted mix of matt white, and a touch of grey no. 64, this will knock off the plastic colour off the Vline brown.
Then apply a wash of varying strength, working on the nooks and crannies of the wagon, this will show the lighter colour after a application of a heavier wash of matt 64.
A spray of Accuflex road grime and a touch of grimy black.
Finally a coat of matt clear will complete the job.
I also recommend that you swap out the couplers for Kadee No. 5's.