For the most part Amtrak is still using analogue channels for voice communications on the Northeast Corridor and DC to Miami. I'm not too sure where Amtrak or other Class 1 Railroads are using IDAS NXDN yet. I do know that SEPTA REGIONAL RAIL has replaced their Motorolas with ICOMs around the same time that the Silver Vs went into service, so they're ready to switch over.