B&M Boxcars

The model of Athearn Genesis 50’ Boxcars what era are they?
What industries did they serve?
Would they end up in the midwest?

I just acquired two them and just curious.
Travis

Are you refering to the SIECO boxcars? If so, their era would be 1970s to present, although I do not know if B&M still has any. For Boston & Maine, I would guess that they served mainly papermills or were leased/rented out to other railroads.