In the railway application, in order to establish the communication between wagons, some technologies are proposed such as the ZigBee and HTN (Hybrid Networking Technology). However, these techniques have some limitations such as: the low data rate, non-secured transmission and interferences. The Ultra Wide Band (UWB) technology presents a good alternative and a good candidate for this application. In recent years, UWB communication systems have received significant attention from both the industry and the academia. In February 2002, the Federal Communications Commission (FCC) allocated 7500 MHz of spectrum (from 3.1 GHz to 10.6 GHz) for use by UWB devices. This ruling has helped to create new standardization efforts, like IEEE 802.15.3a, which focus on developing high speed wireless communication systems. The application of the UWB radio technique in the transport is a more recent topic that is thoroughly researched considering several factors including the nature of the transport propagation environment; the use of adequate transmitting/receiving duty cycle (LDC); the number of devices using UWB technology, the types and levels of interferences. Regulation bodies have considered these railway applications. Impulse Radio Ultra Wideband (IR-UWB) systems have been studied for their inherent advantages of coexistence with narrowband systems with high data rate over short distances with sufficiently small amount of transmitted power. The UWB systems are highly susceptible to interference between the coexisting narrowband systems because of very low transmission power. This paper considers the use of the UWB radio technology for railway application. In this paper, we evaluate the communication performance in constrained environment for the railway application.