The DC FedSMR, previously a Passport system, appears to have been converted to an iDAS system. 407.3750 no longer has traffic on it. 406.5875, 408.4500, 409.8500, and 410.9625 now have iDAS data bursts and what appears to be voice traffic.
An analysis of 409.8500 using DSD+ revealed some system specifications. The frequency was identified as part of "Site 1." DSD+ reported channels 4194306 and 4194310. Talkgroups reported were 50331660, 50331661, 50331662, 50331663, 50331664, and 83886093. The voice was not properly decoded; it's unknown if encryption was used, or if DSD+ was not configured correctly. When DSD+ should have been receiving voice, it reported "MB Voice."
There is limited information on the Internet about FedSMR and this new FedSMR-D system, but look here and here for some.