The Federal Transit Administration has given the Maryland Transit Administration the go-ahead to begin preliminary engineering on the proposed Purple Line in suburban Washington -- a step the federal agency took several months ago for Baltimore's Red Line.

The move puts the Purple Line project, which would extend a light rail line from Bethesda to New Carrollton, in a select group of transit projects nationwide that have reached this step on the road to federal funding approval.

The decision was hailed by political leaders in Prince George's and Montgomery counties, but it could be seen as good news for Red Line supporters in Baltimore as well. That's because the chances of obtaining the General Assembly's support for the projects are enhances if they move in tandem. Neither Baltimore nor the Washington suburbs by themselves have the clout to deliver the votes for the billions of dollars involved, but together they have a chance at funding both. Think of it as the transit version of the deal that brought the Ravens and Redskins to Maryland.