RTD has started the final work on the new southeast extension rail line and that means service disruptions this weekend.The extension will run 2 1/2 miles between Lincoln Avenue and Ridgegate Parkway in Lone Tree.The E and R lines will be shut down from 4 a.m. Sunday until 4 a.m. Monday between the Lincoln and Dry Creek stations. Shuttle service will available every 15 minutes.RTD doesn't have a date for opening the southeast extension, only saying it will be sometime next year.