Potential interferences between train natural frequencies and torque excitation sources are identified. In addition, the influences of torque distribution and coupling design can be assessed using the resulting mode shapes.

Small torsional damping within many trains causes some interferences to be well amplified resulting in large torsional vibrations. To determine the stresses caused by such vibrations, this analysis applies steady state oscillating torques. Locations with high stress concentration factors, such as keyways, are examined for their safety factor against high cycle fatigue failure.

Train startups and electrical events, such as short circuit and recloser faults, require analysis in the time domain. Such events and their resulting motions can also be nonlinear due to the presence of gear backlash, elastomeric or torque-limited couplings. Transient analysis, in conjunction with cumulative fatigue damage analysis, provides a vital tool for evaluating components' life when subjected to these events.