Greg, not sure where I am going at the moment, and a garden railway is a little chicken and egg, unless you buy a starter kit, rolling stock or track both are useless without the other.
I would like to get some track down first, however it boring without something to go on it, hence the Bachmann steamer, but I think I may end up with remote control live steam - but who knows, especially it I don't.
Yep, you're right, and building a garden railway is a lot different to modelling indoors, mainly because you are slightly more time limited - days and seasons, and some of it can be a bit more physical.
So, having worked out my ability for bone idleness and procrastination, when I built the WWSR (at our former house) I decided that it had got to be instant, or it would be a project that never got finished.
At that time, Bachmann US outline was pretty cheap, as was some LGB US outline, and I like lots of wheels; also track power (apart from live steam) was almost assumed way back in 2006.
Sandy Taylor at Scottish Garden Railways advised me to go with a minimum 8ft radius and I'm forever grateful that for once I listened to some advice.
I bought some old railway sleepers, laid the track out round the edge of the garden and got it all down in about 3 - 4 weeks, and then played trains.
After a year or so, I started to work out what I really wanted to do, and slowly moved in that direction, but I could keep playing with my trains, and developing the stock as I went along.
Just a thought, but it worked for me

