Since Fuel Cells (FCs) are very expensive, their output power should be minimized when FCs are applied to hybrid powered railway vehicles. Therefore, it is necessary to reveal the effect of hybridization with energy storage devices to reduce the FCs output power. In this paper, methods to design the capacity of energy storage devices which are assumed to be Lithium-ion batteries (LIBs) and Electric Double Layer Capacitors (EDLCs) are studied for FCs hybrid powered railway vehicles. The proposed methods are verified by numerical simulations, assuming a train operation in a typical rural line. Finally, procedures to select the suitable energy storage devices and to design their capacity for FCs hybrid powered railway vehicles are provided. The results of this study contribute to the development of environment-friendly transportation system.