The weight of each leaf including ballast is about 1070 tons.
The ballast consists of such materials as broken stone, furnace slag, gravel, cinders or earth, the lower layers commonly consisting of coarser materials than the top ones, and its purpose is to provide a firm, well-drained foundation in which the sleepers or crossties may be embedded and held in place, and by which the weight of the track and the trains may be distributed over the road-bed.
The weight of ballast in the short arms of the bascules is 365 tons.
Flint (valuable for railway ballast) occurs in immense quantities about Wymore and Blue Springs.
The intervals between the sleepers are filled in level with ballast, 12'2' FIG.