Direct train-to-train communications at low UHF frequencies

Fundamental modernization of railway transportation is on the agenda of the Next Generation Train (NGT) project funded by the German Aerospace Center DLR as well as the Roll2Rail project within the Shift2Rail initiative. Reliable direct Train to Train (T2T) communication can significantly enhance train control and signaling towards semi or fully autonomous operation, in order to significantly increase the efficiency and safety. With Terrestrial Trunked Radio (TETRA) a communication standard is available with high potential for this use-case. It offers the ability of direct communications between vehicles, i.e. ad-hoc communications over several kilometers. In this paper, we summarize the results of T2T measurements conducted at 450 MHz. We will characterize the propagation conditions and assess the link performance by analyzing transmissions in different scenarios and railway environments