When were these cars used?

[KentBy]

I have accured a collection of HO cars, but I think some don't fit my period. I am trying to restrict my stock to mid 50's, so tell me if I should trade off these cars.

All are Athearn Blue Box.

ATSF 55' ACF center flow hopper.

AFSF 50' Supper Shock Control box car.

ATSF 40' HI-CUBE box car.

Milwaukee Road 40' HI-CUBE box car.

Kent