406.9375 MHz in Las Vegas Identified

For some time I have been hearing Moto TRBO (DMR) on 406.9375 MHz. I assumed for some time that it was related to the VA Medical Center in Las Vegas.

But now I am field testing a DMR capable radio and I can actually hear what is being said on the frequency, it appears to be the US Postal Service, probably a bulk mail center or main mail processing center. There were plenty of references to loading docks and trucks & trailers. But the big clue was references to "Reno Mail" being loaded.

So far, 406.9375 MHz is the only federal frequency in the area that I have found DMR digital traffic on, so I don't believe this is a trunked system.