On your second pic Atlasrob there is a decal on the side with KBR on it.
I think they are private military/security contractors.
If it is the same KBR they are or were a subsidiary of Halliburton, a defense contractor. Oh and nice pics by the way.:usa
That fourth picture in your first lot, whats up with the excavator boom on the top of the tank? Its got its bucket, dipper, boom, and cylinders.
The military seems to over do everything..
KBR=Kellog,Brown and Root.