In this work the antenna propagation has been characterized for a 5G Wireless Train Backbone (WLTB). For this purpose, a train model has been generated and ray tracing simulations have been performed with antennas installed on the roof of the train. In order to obtain the most optimal antenna locations, the position of the antennas has been modified in vertical and horizontal directions. Tunnels have also been simulated, changing their material properties to study their effect on the signal propagation. Obtained results have allowed to identify potential locations for the antennas of the WLTB.