Doctor F.,
From the expanded view the A unit looks like an Athearn underframe. The B unit underfame looks to be an Athearn as well, especially the rear truck (viewer's left), however the front truck assembly does not show the same electrical pickups. Having seen your work for quite awhile now I would not be surprised to find out that you have managed to shoehorn a small block chevy motor into these units .
I await the test results.
John R