Martin, all I've really come up with so far is a schemetic and some ideas...
No prizes for guessing the source of the names! Mainline = black, branches = grey, both single track. Set in the mid-1920s, ie the hedonistic times before the Great Depression. Maximum train length = 4 4-6 wheel coaches + tank engine (see coaches from the Etched Pixels/Ultima catalogue below - very likely mainline candidates, and definitely not my work!). Only tank engines need apply - island distances won't need tenders, and it saves on turntables. Most likely to be in N-scale, both to fit more in and to allow room to breathe (ie bigger gaps between stations, wider scenery). Any fiddle/storage yards will be inserted between stations - again to give the impression of longer distances. I imagine the island to be in the English Channel, a few miles off the Cornwall/Devon coast, granite-based, and with a pitchblende mine amongst the WMC's assets (I fancy having a GWR Bullion Van as the only bogie vehicle on the line, for this expensive and dangerous commodity. St Cecily's can be a world-leading centre for atomic research!).
Bunbury will basically be like Bembridge IoWR, but with a fourth point in lieu of the sector table. Gwendolen will be like your main station, but on a much smaller scale (ie terminus with a through platform for the St Cecily's branch). Port Augusta may be served by a small train ferry - yet to be decided. Merriman's and WMC will be in there somewhere, just not sure where yet. St Cecily's University will be an old monastry that converted itself into a university to avoid King Henry VIII's wrath, and will be overseen by Chancellor Chasuble.
Once I've got something up and running, with at least some scenery, then I might bring others into my world (ie join a club), but I'd like to go solo to start with.
- Scott (in Melbourne, Australia)