Green Line extension wins key federal approval for scaled-back version

The Federal Transit Administration has approved the MBTA’s $2.3 billion cost estimate for the scaled-back and delayed version of the Green Line extension through Somerville into Medford.

The 4.7-mile project was supposed to start opening this year and finish opening in 2020. Also, its seven new stations, including a relocated Lechmere stop, were once supposed to be largely enclosed in somewhat elaborate buildings.

There was also to be a 7,000-foot community path along the extension.

Ballooning costs and management problems, however, croaked those ambitions; and instead the extension will not start opening until 2021 and many of the stations will be open-air, without accouterments such as elevators and fare gates.

As for the community path, officials have shrunk that to 3,000 feet.

Still, it could’ve been worse. Had the feds not signed off on the new cost estimate, it’s likely the extension would have been put on hold indefinitely.

• Feds OK Green Line extension costs, securing project’s future [Globe]
• The pessimist’s guide to Greater Boston real estate in 2017 [Curbed Boston]