General American introduced the Dry-Flo car in 1958, and the Q bought 100 of the 3,500 cubic foot cars the next year. CB&Q ( car numbers ) 85200 - 85299, class HC-4, were delivered during May and June 1959 in the new image gray and red paint scheme, Dry-Flo cars ( were equipped ) with one compartment, 10 loading hatches, six GATC vacuum discharge outlets. Survivors of the CB&Q 85200 -85299 series were renumbered into the BN 475800 - 475899 series, although numbers 85208 and 85217 were renumbered into the BN series 448033 - 448042 .

General American introduced the Dry-Flo car in 1958, and the Q bought 100 of the 3,500 cubic foot cars the next year. CB&Q ( car numbers ) 85200 - 85299, class HC-4, were delivered during May and June 1959 in the new image gray and red paint scheme, Dry-Flo cars ( were equipped ) with one compartment, 10 loading hatches, six GATC vacuum discharge outlets. Survivors of the CB&Q 85200 -85299 series were renumbered into the BN 475800 - 475899 series, although numbers 85208 and 85217 were renumbered into the BN series 448033 - 448042 .

In the early 1960's, Pullman-Standard developed the PS-2CD design, which eliminated the split discharge gates by running the center sill through the inside of the hoppers, thus allowing a single, center-discharge outlet for each hopper, for a total of three outlets per car instead of the previously standard six. Cubic capacity was increased to 4,000 cubic feet by raising the sides another 18 inches and extending the slope sheets all the way to the end of the car frame. Roller bearing trucks of 100-ton capacity were also employed. The Q bought 190 PS-2CD's in 1963, numbering them 85500 - 85689. The first 140 were class LO-4 ( the HC class designation having been abandoned after 1961 ) and featured the traditional 10 circular loading hatches. The last 50 cars were the first Burlington covered hoppers with trough loading hatches and thus were classed LO-4A. All 190 cars still employed the 4/3/4 outside post pattern and had Enterprise gravity outlets.