What voltage are you using? It appears too much vibration is being transmitted to the housing....make sure the nut securing the roof on is not too tight or too loose..snug does it. When adjusting the spring tension, be carefull of the arm the spring attaches to... they will break from metal fatigue. In the October 1999 issue of O Gauge Railroading, Jim Barrett in the Backshop wrote a piece titled 'The Old and the New'. in which he described the the problems and fixes for the 342 Culvert Loader. If you can reference that, it would be helpful. Good luck with it...it's a fun accessory to watch.