The Icom and Kenwood VNB digital systems use AMBE+2 vocoders which is the format being used by the railroads, including BNSF. The AMBE+2 format is not compatible with DStar which uses an earlier AMBE vocoder. I’ve been using the Kenwood version (NXDN) of the AMBE+2 licensed product in the VNB mode for over a year and the performance is outstanding. It’s also possible to program the commercial version of the Kenwood radio to automatically accept either NB analog or VNB digital modes, and respond automatically in kind. I don’t know if the RR version will do that since I’ve only seen the RR version once for a few minutes. The audio quality is excellent, but the latency in the vocoder is noticeable and somewhat disconcerting if the receiving radio is within audible hearing distance of the transmitter. The audio can be shaped digitally to emulate the response of an analog FM radio although with some audio shaping options, the audio can sound somewhat mechanical (robotic). Based on my own experience, I think the railroads will be pleased, and the VNB capability it will give them a nice hedge on the future. I can hear some of the Barstow yard radio traffic from my home in the foothills south of Palmdale so I plan to monitor the test to see how it works for the RR. I can program the Kenwood radio to scan both analog and digital channels in wide, narrow, and very narrow digital modes.