The interest for developing hybrid electric locomotives consisting of diesel engine, regenerative braking and battery storage is growing due to increased demand and cost of diesel oil, uncertainty in the steady supply of oil, and increased standards for reduced emissions. Electrical energy is lost from electric locomotives in the form of heat during dynamic braking. Routing this energy using a regenerative braking system into battery stacks can improve the overall efficiency as it can be used later to provide traction force during acceleration. Objective of this study is to perform a feasibility analysis of modes of regenerating the energy developed in the braking and storing the energy in an electric battery storage system for use in railroad locomotive applications. Various road locomotive duty cycles, charge and discharge rates, and environmental conditions have been considered as this is expected to substantially influence the optimal performance and safety of the battery as well as the potential fuel savings that could be realized using a hybrid design. A computational algorithm is developed to determine the amount of energy that can be obtained from regenerative breaking during the run of locomotive and can be stored back into the stack of battery, which can be coupled with diesel engine to save additional consumption of fuel. A combined electrochemical and thermal simulation analysis of several battery configurations using multiphysics simulation code has also been performed in order to understand the thermal management and cooling requirements of the batteries subject to the charging and discharging requirements of a locomotive engine. Such an analysis assists in addressing the key issue of operating the battery at an maximum efficiency level while dissipating any excessive heat generated during the operation, and maintaining the battery at a desired temperature range using a cooling scheme.