OKRX #: 21 was built for the Great Northern Railroad in 1958 and numbered #: X-21. It had many state of the art features, for the comfort of the crew, that many of the older cabooses did not have at that time. After serving the Great Northern and its successor railroads, it was retired in 1985 and eventually wound up at the Oklahoma Railway Museum in Oklahoma City, OK. It is used on the excursion trains.
