Pullman space on the original consist was found inadequate to meet demands and it had been necessary to operate additional sleepers from the Pullman Company pool. As those cars did not measure up to California Zephyr standards, it was decided to purchase six additional sleepers built to CZ specifications. The three railroads returned to BUDD in 1952 with an order for these new sleepers to be of the 6-5 configuration, with one for each California Zephyr consist. Built to plan 9534 in July and August of 1952 each car contained six double-bedrooms and five compartments. Included in each were enclosed toilet facilities. The bedrooms had a large sofa type seat that was wide enough for two people while the compartments included two comfortable chairs, which converted to the lower berth. The bedrooms and compartments were arranged so eight pairs of those rooms could be combined to create Bedroom Suites, which were ideal for family or group occupancy. Beds in the compartments were lengthwise of the car while those in the bedrooms were crosswise. Each room was also equipped with circulating, electrically refrigerated drinking water, radio, individual temperature control and 110-volt outlets for electrical appliances. All rooms had double width windows. Three of the six cars were built for the CB&Q as 450-452 and named Silver Dove, Quail and Thrush. D&RGW 1135 was the Silver Gull and WP’s 851, 852 were the Silver Crane and Swallow. With this addition transference of cars at Chicago between the eastbound California Zephyr and the Ak-Sar-Ben Zephyr allowed an overnight run to Lincoln, Nebraska with a return two days later in time for the CZ’s departure from Chicago in the afternoon.