One of my tracks on my two track main line is handlaid with oak ties and brass rails. As the weather has changed, we get much more rain and this has lead to my ballast (which is over scale size loose ballast) being invaded by moss. My track is ground level on a concrete base in clayish soil as we are beneath a forest on the north side of the valley's which is a hundred and fifty feet away. Getting rid of this moss is a real chore taking a huge amount of time every spring. it is also getting painful as I grow older. I am looking for a solution to get rid of it chemically with no success so far. The chemical must not harm the wood in the ties, the brass (many use copper oxide...), nor the grass which is next to the concrete base... Qite a dilemna.