Pennsylvania Gray Ballast 105 is a black cinder for any railroad that uses black ballast cinder for the railroad.
1051 N Scale Ballast
1052 HO Ballast
1053 HO Mainline Ballast
1054 Large Scale
After being ejected out of a volcano, cinder/volcanic rock gets its appearance from the simultaneous rapid cooling and depressurization process. Grey Cinder has small cysts, which is what causes it to be so light in weight. We crush it down to make 105 Pennsylvania Gray Ballast
Ties/Sleepers are placed on ballast to forms the trackbed upon which the track placed. It is packed between, below, and around the ties and ballasted to bear the load from the railroad ties, to facilitate drainage of water, and to keep down vegetation that might interfere with the track structure. The ballast also holds the track in place as the trains roll over it. It consists of crushed stone. Many modelers consider ballasting a chore, but one that is necessary to get the right look.
More on Ballast
The ballast for railway modelers comes in many sizes and colors. You will need to choose the size—this dependant on the scale of your model railway. Choose the color because of the location of your railway. Size is critical as over or under size ballast looks wrong. Colour is not as important as variations occurred around the country dependant on what local stone was available. It is possible to combine two colors to create the effect you require, but mixing the materials must be done accurately to allow you to combine the two colors again should you need more material. Choose the size and color that are appropriate for your scale and locale and complement the colors of your scenery.