This is the #7760 Diesel Shunter converted to 9V. This model is reasonably easy to convert to 9V, all you really need is the #5300 9V Train Motor. I have also added working 9V headlights to this model as well. If I ever get a chance I will add more details about exactly what parts are required.
This is now my hardest-working locomotive. I kept the ballast bricks (weights) in the model which are intended to keep the 12V motor's contacts and wheels on the track. They aren't actually needed on 9V trains but the extra weight really helps when pulling very long trains.