I enjoyed the prototype pictures and noted the ballast and siding track dirt. I look at things from a different perspective than some and realized I have those colors. This is the CN railroad, but could be used for a free lance line. The rock on the mainline is very close to my #130-2 Northern Pacific ballast and the sidings are like my #1030 Black Cinder Powder that is also used for Asphalt Paving Material.
Look at the ties where the jointer plate is being replaced. The wood is very splintered and the ties are brown. I have a pigment for this, but don't sell it as of yet.