In its original form, the class CB1 4-6+4-2T, the RSR's one and only Hagans engine, had acquitted itself quite well as regards its patented articulated side-rod drive. Its road-holding, however, left much more to be desired. Between its placing in service in 1904 and its rebuilding in 1907, the locomotive was derailed a total of ninety-seven times. Most of these incidents were minor, some of them even comical, but two occurred at full speed (60 km/h), when running bunker-first, and caused loss of life. The cause of the trouble was never established beyond doubt. The Hagans Company in Erfurt tried to help, since the difficulties were reflecting badly on their patent, but without success. As soon as its designer, Karel Belčamin, got back from his world tour, he had the engine rebuilt with a conventional rigid frame. After this the locomotive gave no further trouble and ran until its boiler wore out in late 1915.