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.