Larger calcium carbide containers were used starting around 1967.  DuPont Chemical had 20 special cars built to carry these larger containers, and AHM made these cars (AHM 5393).  Although AHM labeled the cars as several roads and companies, only DuPont had these cars.  Later, bulkhead flats were used to carry these, with special crossbars and turnbuckle type tie downs. Sold in a set of 14 containers to fit the AHM car. HO only.  Other scales upon request.