Well, I've well and truly fallen under the spell of Llanfyllin, after seeing the photos in the Great Western railway Journal this month.
I've now decided to start work on the station building. This is something that I can work on even before I start on the track etc. although actual construction is some way off yet. I am currently working on producing a 'near-to-scale' drawing in Adobe Illustrator - I say 'near-to-scale' rather than 'scale' because I'm working purely on estimates from the photos. I'm also switching the two ends over so that the two-story station-master's house is at the left-hand end, since my station will be the other way round (don't ask me why - I suppose I could just as easily switch it over to be the other way round...)
Anyway, the idea is to produce a 'scale' drawing that I can use as a template for the actual construction (I started doing it with pencil and paper but soon realised that doing it on the computer made far more sense.)