Capital MetroRail and the City of Austin have joined forces to provide Friday and Saturday nighttime service from Lakeline to the Downtown Station. The new service changes take effect the weekend after SXSW, on March 23rd. The trains will run hourly from 7 pm-midnight on Friday nights and every 35 minutes from 4 pm-midnight on Saturdays.
Cap Metro will review the service periodically to see whether early Saturday service is justified. If eventually approved, the service could be expanded to begin on Saturdays at 10 am.
Finally, Cap Metro is working extend the nighttime service for the entire route, including Leander. This is a separate budgeting issue, however, and may take some time.
For more information see the MetroRail web site.