a discoloration produced by foreign matter having penetrated into or chemically reacted with a material; a spot not easily removed.
a natural spot or patch of color different from that of the basic color, as on the body of an animal.
a cause of reproach; stigma; blemish:
a stain on one's reputation.
coloration produced by a dye that penetrates a substance, as wood.
a dye made into a solution for coloring woods, textiles, etc.
a reagent or dye used in treating a specimen for microscopic examination.
In this case I choose #4.
There you have it. All the ties in Aylmer are stained. We're now ready for the initial application of ballast.
By following this order of steps I avoid gluing points shut on the turnouts. A huge plus for me. I'll have to turn my attention to the backdrop soon. Good thing that goes quick.