Large Airslide Covered Hoppers - Uses/Era
I am interested in learning about the airslide covered hoppers. I have found information about who built them and when. I have found online that they were used for small granular food products (flour, sugar and corn starch?).
My questions are:
- What else did they carry?
- Were many still in service in my modeling era (2012)?
- Are any still in service today and how are they used today (fly ash?).
- If they were used for flour, sugar and corn starch, why do I see Walthers model airslides with Champion spark plug or Firestone tire logos on them?
- Were airslides used for non-food commodities?
Any and all information is appreciated!