What About opening the other side of Austin up to the Rails? A cruise down Mopac on the Rails. A way to connect North and South Austin. This would open up West Austin, West Downtown, Palmer Auditorium and South Austin to the Rails.
What about extending the Rails down 5th street to Airport/183 then down to Bergstrom International Airport this would be a short addition of laying down tracks but has a lot of potential for less than 6 miles of tracks.
For less than 5.5 Miles of tracks if the detour begins at Airport:
Something I just noticed was that there is already tracks in South Austin ending less than 4 miles from the Airport... this could also be extended to create a loop for the Rails around Austin. This extension would currently cost less than the 5th Street/Airport extension which I think we still need to complete a circular route to connect the Mopac South/North Austin route. The Mopac Rail and the Current Rail Intersect on the way to Leander to complete the circular route.
South Austin Rail to Bergstrom International Airport:
The Formula One Race Car track that that is Moving to Del Valle, I would think that the Rail would extend their Service to Del Ville for the Race. This is a major International Formula One Race Track and the extensions to the Bergstrom International Airport will supplement Austin. The formula One race Track is near Bergstrom International Airport. The Rail would be a way to dissipate what is going to be a very large Major traffic issues. Cap Metro could coordinate with Hotels and businesses to defer Costs, for we could build these Rails to work with them. There are bound to be more Hotels and and other businesses around the Airport and the Race track. (This is the route Build your Business here). This track would only need to be extended from Bergstrom International Airport once the Rail gets built to the Airport. This could be used as a motivating factor to extend the Rails to the Airport. There by making all of Austin available and accessible.
Formula One Grand Prix Race track Location:
On a further Note the Mopac rail goes all the way to Buda -> Kyle -> San Marcos -> New Braunfel -> San Antonio -> and beyond... To the North it goes through Round Rock and branches to Georgetown and beyond or east to Taylor and beyond. Not only supplementing North/South Austin but has the future Growth Potential of being a Major Multi City Rail System. The Current Freight Rail in east Austin goes through Manor and Elgin to the east. While these may not be in the current Budget they are something to consider for the future expansions.