5621-5635) were fitted with roller bearings on every axle, lightweight rods, all-weather vestibule cabs and a solid pilot.

Although, the O-5A locomotives were also built with abnormal design features; the seatboxes inside the cabs were positioned too low, and the boilers were humpbacked beyond the sandboxes.

The O-5 class locomotives were capable at traveling at speeds as high as forty-five miles per hour while hauling 125 loaded cars.

[5] As the railroad invested in adding EMD SD9 roadswitchers throughout the mid and late 1950s, the usefulness in the O-5's diminished, and most of them were put into storage, while those that remained in service were solely relegated to operate east of Lincoln, Nebraska.

[8] Between 1955 and 1959, five of the O-5 class locomotives (numbers 5600, 5618, 5626, 5631, and 5632) were used to pull occasional excursion trains for the CB&Q, prior to their retirement.

[12] The locomotive was sold to steam engine caretaker Richard Jensen, who moved it to the Chicago and Western Indiana Roundhouse for storage.