I have 2 proposals I'd like you to consider for future versions.
1. Pause. When you pause the TrackIR or it moves out of the range of sensor make it possible to use the mouse back. Right now you constantly send the last position of the TrackIR you registered that theoretically makes it possible to use the mouse, but as soon as you release the right mouse button you're back at that possition.
2. Driving backwards. If you have a loco that can drive backwards (e.g. German 294 or some steamers) the TrackIR is basically useless. What could be done is to have an option to reverse the central point by 180 degrees backwards. To have the point directly behind you as a central one. This way you could drive both ways with TrackIR. I know you hook up directly to the TS functions that set the camera. So this should be possible. This could be switched with a keyboard shortcut. You could register a shortcut with a RegisterHotKey, e.g. Shift+Alt+R: