Just got my son the Tweetsie G Scale and had the same question.  I put velcro on the deck and on his feet and works fine.  He is able to move him around this way.  Hope this helps  Charlie

Hello All, I'm new to the site.  I just bought my son a large scale Tweetsie version and ran fine for several days.  I have noticed that at start up we have to push to get moving in either direction.  I wiped down the track with a dry cloth.  Any thing else we should do or look for?  Thanks  Charlie