There’s momentum at last for East-West Rail, but Postal Service still stands in the way

A key lawmaker is renewing pressure on the Postal Service to move its huge sorting facility alongside South Station, to enable the expansion of service at Boston’s biggest rail hub.

But there’s one big obstacle no one seems to be talking about: the US Postal Service’s sprawling mail-sorting complex along the Fort Point Channel. State officials can do all the track and station work they want out west. With the massive USPS facility blocking a South Station expansion in Boston, East-West Rail could be going nowhere.