Title says it.
This forum does not appear to offer a members' "for sale" section, so, apparently, not here.
Some other model railroad forums do offer members a sub-forum to sell things: "Swap Meet" on the "Trainboard" forum https://www.trainboard.com/highball/index.php?forums/trainboard-swap-meet.151/ and "Trading Post" on "The Railwire" forum https://www.therailwire.net/forum/index.php?board=12.0 . But, you have to join those forums and make a specified number of posts before you have the privilege of posting to those subforums. But, joining other model railroad forums is a great idea, anyway. They are free to join, and they provide a wealth of information and advice that is not found on manufacturer-specific forums like this one.
And, of course, there is eBay, where buying is easy, but selling takes more effort than those model railroad forums. I get a lot of my stuff from eBay, including things that are no longer still available from Bachmann.
;D
Facebook groups are also another, ever-more popular, place to buy, sell, and trade model railroading items (eBay is becoming more and more expensive due to fees). There's also Craigslist.