Thank you for your response. It did improve performance to clean the center of the switches. (FasTrack) My guess is that as a loco traverses the switch in the curved direction the roller does a "drift" action which causes more gunk to build up. As this is a first Atlas 3 rail for me I have yet to determine how to take the shell off and Atlas hasn't put any info on their website.
Would installing a battery make any difference?