For people saying we can rebuild the entire system for this: the number is inclusive of not only the entire subway (light+heavy rail), but also the Commuter Rail, the entire bus network, and all the support/maintenance systems for them. SGR also has various degrees of priority and need: just because something falls out of SGR doesn't mean it isn't still functional. It also isn't going to be $25B upfront all right now. I would expect, again, the MBTA to come up with a 5 or 10-year plan to address this would be $5b to $2.5B a year over that time period. This brings me back to my original rant: is it even really $25B when a seemingly whole bunch of this stuff is already underway and paid for?