Lionel engine wheels sparking

[mrmet6986]

I have the Lionel 6-8480 F3 powered A unit UPC diesel engine. It runs great, no hesitation and cycles thru forward-neutral-reverse smoothly. BUT when it is running all the wheels start sparking on my Lionel FastTrack. The track does not short out but the sparking is disturbing. I tried running it on my standard O guage track and it does not spark but as soon as I reach a certain speed the train does continue to run and the track does not short out but the green light on the transformer starts blinking.
I opened the engine and I do not see any loose or damaged wires. The engine is in excellent condition except for the fact that it sparks.
I am not sure what to look for at this point. What could be causing the sparking and why does the transformer light blink when run beyond a certain speed?

Thanks

[Eriediamond]

I'm no expert, but in my opinion the sparking comes from dirty wheels-track. My old scout set that I had back in the late forties did the same thing. I think the reason it doesn't spark on the tubular track is because of the shape of the rail - more contact area. Having said this, I think if the wheels are cleaned and the track the light will stop blinking. Just an opinion.

 

[mrmet6986]

You were right on target. Did a thorough cleaning of all 8 wheels (they actually were so dirty I could scrape off the dirt) then oiled and greased the gears and axles and now it runs great.

THANK YOU!!!

[SCAUP]

I suspect a clean motor, clean wheels, new roller with a strong, properly adjusted collector spring, good, intact wires & no short-connections and a clean track will be almost spark free.  I say almost cause I've got a couple of spark producing hummers that are winning this battle.