Good points Martin. I have a number of plans which I would love to translate into the Trainz Model paradigm, but tunnels in particular make it impractical, as does building multiple overlapping tracks. Even scaling up the plan (I tend to set OO/HO plans to TT scale in Basemapz) doesn't always help. Several of the old Peco plans from the 70's are crying out to be done and I have a lovely plan of a layout based on Blair Atholl from an early 1960's Railway Modeller that has defied several attempts to reproduce.