I have been in electric trains for years starting in the 50s with American flyer.  Now into HO and very experienced.  I bought my grandson the Bachmann G scale Tweetsie set for Christmas, which is today.  We simply could not get it to run.  I checked over all the standard problems suggested in the manual and all those issues were correctly done or not a problem.  The rheostat (speed controller) lights up so the transformer is apparently sending juice through it and the electrical outlet is a good one and the clips on the underside of the rails appear to be making good contact.  However, when I remove the "clips" that carry current to the rails from beneath the track and lay them instead across the top of the rails (with of course one clip on each rail) , I should see some "sparking" or some sign of life with the AC electrical system but I don't.

In the instruction manual it refers to a "polarity switch" that is under the smokebox front on some Big Haulers, but my Tweetsie on the front of the smokebox has one on/off switch for the smoke unit and above that just a blank hole with "NMRA" imprinted on the left and "European" on the right but no switch.  I am assuming this loco is not equipped with a polarity switch?  If it's supposed to be, then mine is not visible and I suppose could have fallen down inside the smokebox somehow?  Anybody know if this loco is one that is not supposed to have this switch?

Anybody have any other bright ideas?  I have a very disappointed 7 year old grandson and believe me, his grandpa is not so delighted with this set either, Bachmann!!  I bought a big Hauler set several years ago (since sold) and it was up and running with no problem but this one.................