I think the Atlas forum reached its height in 2004-2006, and has been in decline ever since. I'm not sure what happened but people started showing les,, contributing less and arguing more. Its probably a good time to put it to rest.
I have had an account there since at least 2002-2003, but don't post much there anymore. TB has a lot of features that Atlas does not, but I am probably most at home over at therailwire.net, where we have formed a merry band of missfits and northeastern modelers. Sad to see Atlas Forum go, but hope that energy is used to benifit N scale.