Unbranded Antique Bottom Bracket possibly for Tandem Bicycle

Fair condition.
The exact identity and purpose of this part is a mystery, but it appears to be a bottom bracket from an antique tandem bicycle. The housing has both inner and outer bearing surfaces that would allow the whole unit to spin inside the frame bottom bracket shell as well as allowing the spindle to spin inside the housing. 
79mm overall width.
45mm housing diameter plus bearing race.
Bearing surfaces are in fair condition showing some wear.
Includes left and right bearing races and locknut.
One race is threaded and one is not.
Includes left and right inner bearings.

Unbranded Antique Bottom Bracket possibly for Tandem Bicycle