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
= 0.09 meters
Figure 1.8. Pneumatic Tamper.
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.