much simpler
Also proposed is a "guided bus" line running from a station on exisitng Glasgow-Edinburgh track half a mile down the road.
I reckon the best system would be a Metro-style train which could cover much of Edinburgh in similar style to the one in Glasgow, with shuttle to airport from town centre and said stop on main line.
Could also double up as a park and ride to avoid the awful queues from Glasgow and the Forth Bridge past the airport all the way into town. But then I would say that, I have to sit in it.