The hydrogen fuel cell-based rail propulsion technologies powered by PEMFC (proton exchange membrane-based Fuel Cell) along with a suitably sized battery bank are being tried out globally for powering railroad vehicles. Indian Railways plans to convert the existing 700 HP Narrow Gauge ZDM3 Diesel-Hydraulic Locomotive running on Kalka- Shimla section into hybrid fuel cell and battery-based Locomotive. The proposed work is related to the development of design optimisation (DO) approach for the optimal component sizing of FC-based hybrid energy system (HES) along with an energy management optimisation (EMO) approach for the optimal energy management of the HES components.