Vanishing locos - crashing sim

I have been getting reports of my FT not appearing in the sim or appearing in the editor then disappearing. For others it is OK.
I am now having the same problems and I notice whatever the problem is it affects my GP9s too. The child parts, crew, horns, fuel tanks, appear, disappear or are floating above the loco
This is a worry (and most frustrating) as you can see from the various pictures and movies I have posted in various forums things were working well
Any suggestions?
Dick
I am now having the same problems and I notice whatever the problem is it affects my GP9s too. The child parts, crew, horns, fuel tanks, appear, disappear or are floating above the loco

This is a worry (and most frustrating) as you can see from the various pictures and movies I have posted in various forums things were working well

Any suggestions?
Dick