Hiya, I lived in Dundee for three years, catching the train everyday to Perth. The line splits just before the bridge, and the east end does indeed go into a tunnel exiting in Dundee itself, and then it goes on to Carnoustie, Arbroath, Montrose and all staions to Aberdeen.
Take a look at Google Maps
http://maps.google.c...F-8&sa=N&tab=wl
There used to be a yard there, and a long time ago a shed. A resident 06 shunter, this is now gone, and replaced by some brand new buildings.
The still store the odd unit in there, and and freight.
Would make an ideal layout, if you had the space.