It's a session, and a multiplayer one at that.
The session name is A & SLT Multiplayer Industry AI Sandbox, kuid:441662:100002. According to my CM it's on the DLS, and it must be available somehow because I've run it on the server and someone has joined it. The session mostly works as-is, the update will fix an omission from an AI driver (Alcaron) command sequence, replaces driver Giro56's Southern Pacific loco 8644 that apparently doesn't load in multiplayer, and derailment realism has been set to None, which hopefully switches off derailments, as one can get airborne in places on this route while observing the speed limit.