Propagation time delay spread measurements at 915 MHz in a large train yard

Time delay spread and path loss measurements were performed in a large, active train yard to support development of intra-yard wireless communication systems, such as those intended to communicate with individual railcars and for track-to-terminal communications. Propagation measurements focused on three sites within the train yard: a close-in site, a parallel-track site, and a cross-track site. The maximum RMS delay spread was 1161 ns across cross-track measurements. Parallel-track measurements yielded a maximum RMS delay spread of 732 ns, while close-in measurements showed a maximum RMS delay spread of 281 ns. Upper bound path loss exponents were found to be 2.7 and 3.4 for the parallel- and cross-track sites, respectively.