Something odd when editing sessions

OK, I'm puzzled, and hope someone might have a suggestion or two for me.
This happens consistantly in at least two routes so far. These are the GB Bighorn, and the CSX Mainline beta.
When I try to create a session or create a new one, all the turntables and transfer tables disappear! Not just visually, but completely. I can drive a loco right into the turntable pit. If I exit the session and re-enter it the assets are still gone.
If I load a different session, or edit the route itself they come back. But then if I try to create a new session they go away again. So far I've only tried it with these two routes; I'm afraid to try any more of them
Any ideas? Anybody???
This happens consistantly in at least two routes so far. These are the GB Bighorn, and the CSX Mainline beta.
When I try to create a session or create a new one, all the turntables and transfer tables disappear! Not just visually, but completely. I can drive a loco right into the turntable pit. If I exit the session and re-enter it the assets are still gone.
If I load a different session, or edit the route itself they come back. But then if I try to create a new session they go away again. So far I've only tried it with these two routes; I'm afraid to try any more of them
Any ideas? Anybody???