LIMESTONE RAILROAD BALLAST. Over 3 million tons of Texas Crushed Stone's crushed limestone has been used for railroad ballast. Railroad ballast is typically graded from 1 ¾" or 1 ¼" to ½". Ballast is open graded and washed over a screen as part of the production process.
Table 68. Recommended Ballast Gradations. Amounts Finer Than Each Sieve (Square Opening) Nominal Size. Percent by Weight. Square Opening. ... suppliers do not stock AREMA gradations, the following AASHTO (highway) ... Subballast is a layer of material between the top ballast .