Problem with Avis Yard Work session

I wonder if anyone else is experiencing this problem with this built-in session. I am using build 90945. Start the session, switch to Realistic mode and use the - key on the keyboard to go to the back of the train and when I do so I cannot control the loco using the keyboard (keys such as w, f, r etc do not work) when I press these keys the hud flickers. If I use the + key to move my view to the front of the loco these keys work. Controlling the loco using the mouse and the display at the bottom right-hand side of the display works regardless of my viewpoint. In order to troubleshoot the problem I started a new session using Kickstarter County Route. I put in a steam loco (same loco used in Avis Yard Work session). and attached three tankers to it. Set it up for realistic mode and I am able to control the steam loco via the keyboard regardless of my viewpoint of the train. This indicates to me that Trainz is working properly and that the problem is with the session. So using C & O Hinton Division route I created a new session. put in same loco and attached 3 tankers and set it up for realistic mode. When I run the session I cannot control the loco as a matter of fact the display which normally appears at the bottom right-hand side of the display is non-existent. I then exited driver and edited the session by removing the last tanker and ran the session again. Now it works properly. I reported this problem to Trainz but they say they cannot see this problem. I went as far as un-installing Trainz and downloading it again from the internet (a lengthy process). Same problem, did an extended database repair same problem. Is someone else experiencing this problem? Maybe Trainz people don't want to fix this problem. I am not a neophyte when it comes to computer usage or using Trainz for that matter although there are people on the forum who are far more knowledgeable then me on Trainz. So if someone is able to duplicate what is happening to me I would appreciate hearing about it.