Running MTH Engine from a Foam Cradle

SD60M posted:

I want to run an MTH engine...upside down...in a foam cradle in order to clean the wheels.  Seems pretty easy and it is.  I can get this to work just fine...but, only if I use the wheels as a "ground."  Should there be...or is there another source of "ground" that I should be able to attach my grounding lead to...other than the wheels?  All the wheels turn...so, what is the best way to achieve a "ground?"

Thanks for any kind response.

Just my opinion but, I wouldn't run a steam locomotive model upside down. Diesels are no problem.

Hot Water makes a good point.  Your choice.  Please make a note of what I want to pass on.  Under no circumstances run an MTH P47 Pacific upside down.  The valve gear will bind after you get speed up and will blow your side rods into a huge mess.  Most others will work.  Not the P47.  

Unlike most train nuts...I own very few replicas of steam driven locomotives...so, no problem here.  My diesel does run just fine as long as I hold the ground lead to the wheel as it turns.  I was hoping to find some "spot" on the frame...have not found that one yet...that I could attach the ground lead to...and be "free" to run the locomotive.  I understand all the cautions about steam engines...what do you say about grounding the diesel?

SD60M posted:

Unlike most train nuts...I own very few replicas of steam driven locomotives...so, no problem here.  My diesel does run just fine as long as I hold the ground lead to the wheel as it turns.  I was hoping to find some "spot" on the frame...have not found that one yet...that I could attach the ground lead to...and be "free" to run the locomotive.  I understand all the cautions about steam engines...what do you say about grounding the diesel?

Since it is a diesel model, I would think any of the screws that hold cover gear plates on either truck, should be a "ground".

Okay...that works.  I know I made this too difficult...some of us (me anyway) need more help than most.