3, the hst (that came in the set) railroad 0-6-0 pannier, and an older 101 dmu. Turned the pannier and hst upside down and applied power to both and ran perfectly but when on track they cause the cut out. To a relatively new modler this is really confusing. I suspect its the controller/power supply so going to look at upgrading to a Hornby hm2000 or something else if there's better recommendations.