The affinitymask=14 is set by ASN. And that is the only other addon I have other than your program GSX.
A weather engine, and precisely the one other users reported they had problem with...it was said Opus was much easier on Simconnect.
The disappearing occurs only with trains that are transporting one of the new large containers. If the train has only regular containers, everything has been properly visible.
The train doesn't know anything about what it's transporting, so this cannot be possibly related. If you had issues like missing files for new container, only the container should have disappeared (and you'll probably would see some error), not the wagon too.
I did experiment by limiting my frame rates deliberately to 30 FPS within FSX but the issue was still present.
Limiting the visual frame rate won't solve any issue caused by addons clobbering the Simconnect with commands, if this was the case. And neither issues caused by the Affinity mask.
[qutoe]I do also use UT2 traffic set to maximum but all the aircraft were fully spawned long before I called for loading and this happened before in a very low traffic remote airport.[/quote]
Haven't you just said ASN was the only other addon other than GSX ? Even if the UT2 traffic has been fully spawned, that doesn't mean UT2 has stopped sending commands to the sim. It's continuing to do that, because it must monitor all its traffic, to control the density, turn it off after a certain distance, etc.
However, I'm not saying those two addons are surely the cause but, it's only the most likely cause. If it was a problem with GSX, you should have seen some kind of error.
It's also possible something external, non flightsim-related might cause this. Simconnect communication happens through named pipes, which is a kind of internal filesystem not stored on devices, but in memory, which means it might be affected by any external software (like antivirus, firewall, etc.), which checks and monitor any file activity. And, with some systems, Simconnect communication can be configured to use TCP, so it might also related to software that checks the network, again a firewall or antivirus.
Or, something else entirely like: how much free memory you had at that time ?