And yet more thoughts ...
After writing the above posts, I had a look at a model railway track plan which I used nearly 40 years ago, by Cyril Freezer (of course!) in Railway Modeller magazine November and December 1956. This was an 8' x 6' U-shaped layout, portable on six baseboards, two 4' x 1', two 3' x 9". and two 3' x 2', a small rural terminus on one leg of the U running to a "fiddle yard" (hidden sidings, manual remarshalling point) on the other leg, via a 2' 6" radius semi-circle. (For those unfamiliar with a fiddle yard, this was an idea invented I believe by Cyril when everything to do with railway modelling was in short supply and modellers were usually faced with making their own - almost everything. The FY represents the rest of the railway system and trains can there be re-arranged by hand, with operation concentrated on the station - not possible in TRAINZ although portals could be used.)
In about three hours work I laid out the track, basic station features and signalling on one TRAINZ baseboard, replacing the FY with a second station. The 2'6" semi-circle (58m in 00) became one of 250 metre radius, much more realistic; the rural terminus took a loco and eight BR Mk1 coaches instead of a small tank loco and two coaches; the goods yard grew in length; and the whole thing looked much more realistic. The FY was replaced by a second station with two platforms of unequal length - perhaps a small town. Overall capacity probably about the same, which was five complete trains plus a few specialised vehicles. For many people at the time, these would have taken a good few years to construct.
Other advantages: between 80 and 100 metres from stations and track to the nearest baseboard edge, so room for realistic scenery. No baseboards and legs to make and join together, no wiring or point controls, almost instantly ready for use in one small part of the house (computer desk) instead of in a shed, and the scenery can be changed instantly if I want to without hacking away at plaster. And it can become another country if that appeals.
A disadvantage? - it can't be taken to an exhibition. But I don't do that any longer.
Incidentally, I used TRAINZ fixed track lengths in my usual way - as aids to planning, templates for curves, replacing them with spline track later except perhaps where short straight "anchors" were needed between spline points. In Britain at least, track outside station limits is seldom straight, but laid on sweeping curves to take account of natural contours and avoid expensive civil enginering work.
Ray