Hi Steve, no need to run for cover.

That is the beauty of a forum like this, you can discuss ideas and also get different opinions.
You are quite right, I doubt that a tunnel would be built under a castle.
There is a railway line very close to the original castle in Austria that this model is based on.
Your thought also gives me another idea, if I do run a tunnel under the castle I could always model some dungeons with skeletons for the trains to run through which can then seen by the camera car.
