Computer simulation techniques have been used to study and evaluate the potential of hybrid locomotive applications. The Longitudinal Train Simulation (CRE-LTS) software package at Centre for Railway Engineering, CQUniversity, Australia has been used to conduct the energy usage analysis for the heavy haul operations on two typical track routes in Australia. The simulation results showed that the energy generated and dissipated from dynamic braking can be up to ~30% of the locomotive traction energy usage for the track routes and train configurations analysed. The further analysis showed that the locomotives operate at an average power of much less than 100% full power, and an energy hybridisation potential factor was defined. The maximum energy hybridisation potential factor was calculated at 63.4%. There is potential for heavy haul hybrid locomotive applications if cost effective technologies are available.