MINNEAPOLIS - Heavy construction is done, so why isn't the green light rail line open yet?

"Really this is our testing and training year," says Laura Baenen, communications manager for the green line which is still on schedule to open in mid-2014.

The new line will link downtown Minneapolis to downtown St. Paul, passing right through the University of Minnesota campus.

While the track is laid and construction on 11 new stops is mostly complete, there is still plenty of work going on behind the scenes.

Crews have spent the last year running wire above and under ground, 170 new workers need to be trained and then there is the issue of rail cars.

"We still have 20 light rail vehicles to take delivery of. They are being manufactured and shipped here from California," says Baenen. "Once we get each one of those light rail vehicles, each one needs to be tested."

That testing has been taking place overnight, when it causes the least amount of traffic disruption.

An official opening date is expected to be announced in late January, but project officials have always said they'd like the green light rail line operational by the time Minneapolis hosts the Major League Baseball All Star Game on July 15.