Your best bet is probably OneVoice network. They have alot of unidentified buses/transportation talk groups.
Generally, on these DMR systems its very hard to track down the exact talkgroup based on voice traffic and activity alone. Especially if the transportation company covers a wider area.
I havent realy seen any new activity on the east mountain DMR system or NYCOMCO. The East mountain System basically went silent over the past summer because there aren't a ton of users.