It's another step forward for the Metro Green Line as overnight track testing on a portion of the new light-rail line will begin this week.

During the overnight hours, a light-rail vehicle will draw power from the overhead lines and will operate along University Avenue between Stadium Village at the University of Minnesota and Fry Street, which is two blocks west of Snelling Avenue.

That prompts a warning to drivers to be on the lookout for trains anywhere along the test segment.

The first live wire test of light-rail vehicles occurred last month when cars traveled between Stadium Village and the East Bank of the University of Minnesota.

No permanent street or sidewalk closures will be in effect, and all traffic controls to facilitate train and vehicle movement through intersections will be in place, Baenen said.

Testing on the eastern end of the line from University Avenue to downtown St. Paul will take place later this fall, said Laura Baenen, a spokeswoman for the Central Corridor Light Rail Project.

When it opens in in mid-2014, the Green Line as it will be called will operate on an 11-mile line between downtown St. Paul and downtown Minneapolis.