These were the final type of caboose to be obtained by the Katy. Two groups were delivered from different manufactures, 125 - 134 from the Darby Corparation and 135 - 142 from the International Car Company. The first group was delivered in 1966, with the nearly identical Darby cars arriving in 1968.

All were delivered in the Barriger red paint, most were repainted in Whitman green with yellow strips. At least four of the Darby cars were donated by the UP for display, one on display outside the recently restored Boonville Katy Depot is the ex-MKT caboose 134. Another is the former 1976 USA BiCentennial decorated, Spirit of 76 caboose at Windsor, Missouri.

Infomation from the Caboose Corner series by Jerry Pitts in the June 1991 Katy Flyer.