https://groups.io/

If you are a railfan, railroad historian or modeler, you just have to try out this site!  When you access the site you can subscribe to a huge number of railroad-related groups that provide a lot of great information, and are super places to ask your most burning questions. There are a few curmudgeons, but most members are wonderful folks that are sure to help out.  Your webmaster follows the DCC, Digitrax, wiringfordcc, ATSF, BN, BNSF, and  RealSTMFC (steam-era freight cars) groups to help out with ARM tasks,  But it seems that almost every railroad-related activity and railroad is covered in one way or another.