published data able to be found showing the actual
range and peak values of impact for normal
operation of trains, and certainly none were found
for the defined interstate network. The value of
230kN is therefore a desired upper limit rather than
a measure of real maximum forces encountered on
track.
A comprehensive investigation of actual impact
forces was undertaken as part of the Rail CRC
project at QUT [4]. Over a year period data was
gathered from two Teknis Wheel Condition
Monitoring stations located on different heavy haul
mineral lines. The loading data from a total of nearly
6 million passing wheels was measured, primarily
from unit trains with 26 to 28 tonne axle loads, in
both the full and empty states. An analysis of
Leong’s data from one of those sites is shown as a
histogram Figure 2. The vertical axis shows the
number of axles on a log scale, while on the
horizontal axis is the measured impact force from