• laborer hours per mile
• raw materials cost per mile
• admin cost per mile (laywers, permits, etc)
• cost per hour of laborers.
• land acquisition costs
It basically has to be one or more of those factors is very inflated in the US. I kind of suspect its laborer hours per mile, and the media is hesitant to pick a fight with unions to publish that.
We suck at building railroads because we never do it.
A century ago we were the best at it, because we did it all the time. But the muscle memory you build up by having an industry devoted to doing something is lost in a generation or two, when you stop.
My friend's neighbor's house burned down a little while ago, also in Massachusetts, the land of said Green Line.
Apparently they needed to alert their neighbors (my friend included) with flyers outlining their plans, followed by some sort of public meeting, before they could begin rebuilding their home.
Imagine being homeless at the mercy of every one of your neighbors and any one of them could arbitrarily slow you down with irrelevant concerns. This kind of tedious bureaucracy is not just inefficient, but very cruel.