A computer simulation technique – the longitudinal train simulation (CRE-LTS) software has been used to study and evaluate the potential of hybrid locomotive applications in the heavy haul operations on a typical track route in Australia. The study envisages a freight heavy haul operation on coastal undulating track rather than typical pit-to-port operations with large altitude change [1], [2]. Based on the simulation results, the train energy usage and the energy from dynamic braking are analysed. The simulation results showed that the locomotives operate at an average power of much less than 100% full power. An energy hybridisation potential factor is used to evaluate the hybridisation possibility, with its value of 54%. It means that there is high potential for hybrid heavy haul locomotive applications. Methods for practical hybrid applications are suggested and discussed.