I've re-read this excellent thread again with interest.  It begs a question: 
  
Does anybody have a video of an A or C class demonstrating the chassis starting, low speed creep, stopping, and crawling over point work? 
  
The videos on the thread show A/C class models already running at speed.  What I would like to see is a video of a chassis that has proven its smoothness and crawlability starting off.  Ability to haul a load once moving is great, but how smooth can some of these chassis be starting and stopping slowly?  I'm not sure a 15:1 gear ratio can do this, but I could be mislead.  Bachmann chassis have much higher gear ratio which is why they perform in such a scale like manner.   
  
Reason is, I am keen to get, acquire, build, or commission a few C and A class models, but only if I can get them running on quality performing chassis. 
  
Has anybody tried the Athearn SW1500 chassis with a SF C class kit? 
  
Thanks in advance.