RivaRossi switcher doesn't run

[Boyd]

I emailed the factory and got an auto response stating it was after business hours. Hopefully I can get some help since I got it on Ebay.

[rtraincollector]

with above said one insulated wheel should be on each side thus you have 2 rails one for each field of power. 

[cwburfle]

If it was my engine, I'd look for a wiper that is out of place. That is, a contact that rubs against either the axle, or the wheels. Sometimes wipers go against the back of the wheel, other times, against the tread.

It is also possible that you reversed the wheels, so the insulated wheels are on the wrong side.

I am not familiar with that exact piece.

[Boyd]

Great Northern 4 wheel DC O scale 2 rail switcher ran when I got it. I was curious about putting 3 rail type wheels on its existing axles so I removed the bottom cover. Doesn't look like it would be very easy so I put the cover back on and it doesn't run. I see the wheels on one side are insulated from the axle. I removed and installed the cover six times without success and I'm completely lost as to what's wrong. The DC motor works.