Performance analysis of an improved energy aware MAC protocol for railway systems Recent advances in wireless sensor network (WSN) have made them potential enough to be used in monitoring railway tracks, rail tunnels and railway monitoring systems. The key requirement in the design of such WSN is to minimize the energy consumption so as to maximize the network lifetime. This paper proposes an improved medium access control (MAC) protocol, namely, time adaptive-bit map assisted(TA-BMA) protocol, for the purpose of communication between the sensors placed in a railway wagon. This protocol is suitable for low to medium traffic applications by shortening the active period of nodes in their respective time slots. Simulation results demonstrate that the proposed TA-BMAprotocol outperforms the existing energy aware protocols, namely, energy efficient adaptive Time-division multiple access protocol (EA-TDMA) and energy efficient bit map assisted protocol (E-BMA) in terms of energy efficiency by 29.20% and 6.39%, respectively.