| Summary: | Back injuries and other illnesses for Tranz Rails Locomotive Engineers, is claimed to be
attributed to vibration of locomotive cabs. The purpose of this research was to conduct a
study in order to determine the complex motion of a DFT locomotive cab and to
objectively and quantifiably measure the vibration present in the locomotive.
This thesis examines the ability of a six Degrees Of Freedom rigid body mathematical
model of a DFT locomotive cab to determine the natural frequencies present. The goal
was to use this model to provide information on different mount alternatives, in order to
reduce vibration. The results of this model were inadequate for the selection of another
elastomeric mounting alternative. While experimental test of the locomotive cab showed
that the rigid body assumption was valid it was found that there are other continuous
vibrations and non-linear effects that are also very important in determining cab
vibration.
Auto-correlation results from acceleration measurements at the base of the mounts were
overlaid with the cross-correlation of the acceleration measurements of the cab side of the
mounts. These results showed that the current mounts have 100% transmissibility. In
some cases and directions the mount was shown to actually amplify the vibrational input
from the locomotive.
The amplitude of the steady-state vibration of the locomotive cab that was being
transmitted was so great that it rendered the dynamic characteristics of the cab
insignificant. From the experimental results, the elastomeric mounts were found to be
incapable of attenuating the vibration. In addition, the vibration levels due to locomotive
running are found to be well above comfort levels of various publications.
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