length of track is given in kilometers, the amount of
raise in centimeters, and the width of the ballast
section in meters, then they would need to convert
all of the dimensions to one common unit. In the
example given here, the measurements are expressed
in meters to arrive at the volume of ballast needed.
Length of track = 7 kilometers = 7 x 1, 000
= 7, 000 meters
Amount of raise = 9 centimeters = 9 x 0.01
Figure 1.8. Pneumatic Tamper.
= 0.09 meters
Width of ballast section = 4 meters
7, 000 x 0.09x4 =
2, 520 cubic meters
When track is raised as much as 4 inches,
enough new ballast must be distributed in advance of
the raise to support the new elevation and maintain
the original section. For smaller raises, it is better to
use the existing ballast to support the new track
elevation, and then restore the original ballast
section by placing new ballast.
Either special ballast cars or drop-bottom
hopper cars may be used to deliver the material to
Figure 1.9. Electric Tamper.
the work site. Then the ballast maybe spread by
using the special car, the hopper car, the Jordan
spreader, or a ballast regulator. The special cars are equipped with pockets from which the material is dumped.