I posted several days ago about a new Kato F7 in N scale not being able to pull several cars up a 2.5% incline (yes, I know it's a good idea to keep that down to 2%, but I'm experimenting with what I have). Having seen the ads for Bullfrog Snot and also noting it's price, I thought I'd try an alternative. First, I went to Radio Shack and found Micro 1-1/8" Smooth Clip test clips - those allow me to hook up to the power pack when the train is upside down. I then rummaged around and found some Performix Plasti Dip multi-purpose rubber coating spray I had around the house (it's used for putting non-conductive coatings on tool handles, among other things). Next I got the loco ready - hooked up the test clips and used blue masking tape to cover the entire rear of the loco except for the rear most pair of wheels. Then sprayed several thin coats and allowed to dry for a day and a half.
My report is that it seems to work just fine. Loco pulls 10 cars up a
2.5% grade with zero slippage and no apparent change in speed going up or down.