Thanks guys.  I just did not want to burn up an engine with using the incorrect controller. Question answered. A special thanks to Bob for a quick reply. Take care from Austins Dad.

My son has mostly Bachmann trains and I would like to clear up a question regarding the speed controllers.  Austin has a G, HO and now an N scale train.  We got the HO first and then the G and now we have gotten the N scale. The colors and the part numbers are different between the G and HO scale speed controllers. We bought a N scale train and the speed controller is the same as the HO scale train, in color and part number. Is this correct? On the ouside of the set is a controller that is red in color. When we opened up the box it had a dark grey knob and had the same part number as the HO set. One can only assume that the reson for the difference in color is so you do not run the incorrect controller on the incorrect scale.  I will not run the set untill I can get this solved. I do not want to burn up an engine. Does anyone out there have the speed controller for an N that is different then the dark grey that I described?  And/Or the differnces between the controllers ie part numbers and internal differences? I'm new here so be gentle. Thanks in advance from Austins Dad