So I have the basic non-sound equipped large scale Thomas.  I want to add the Bachmann DCC Sound module, but I also want to have DCC control of the engine as well.  Is this board just the sound, or do I need to add another chip as well?

So I did a search and came close, but not quite to the answer of my question.  So here goes.
I have the Bachmann North Pole and Southern passenger car set.  Actually 2 sets.  I've had them at least 10 years, and the couplers have finally gotten to the point of needing replacement.  The local Hobby store recommended the #5 as being the standard, most common coupler.  Much nicer...should have done this 5 years ago.  Except...when I shunted the train into the siding and bam...multiple derailments, cars tipped over...and my son informing me "Daddy...bash!"  That's when I discovered the radius clearance doesn't work as well as the replaced whisker type coupler.   
Some searching here leads me to think I need to ask for the #148.  The clearance I'm looking for is essentially two 18" radius curves in a "S".  Does the #148 have a wider swing clearance? (Not sure of the terminology here, sorry!)