Recent centering discussion prompted me to post a note reminding y’all that I produce coupler boxes to fit Sergent (wide and narrow shank) which allow for centering using his friction spring.  Available in 3 colors.  8 car’s worth of parts for just $19 + postage.

http://www.smokymountainmodelworks.com/HO_draft_gear+cplrs.html

Jim King

www.smokymountainmodelworks.com