The SAS is a joke, putting its name on the same list as actually impressive feats like the proof of Fermat's Last Theorem insults everything else on the list. It's the most expensive subway line worldwide per mile, ever, despite the existence of technology that made tunnelling easier. Inflation adjusted, it costs more per mile than hand-digging one of the PATH tubes with 1900s technology [1]. Its cost and duration are almost entirely due to politics and not technical and logistical challenges, including the MTA political fiefdom fighting the Park Board political fiefdom, make-work-program labour spending, staff paid to have their thumbs up their asses in the tunnels [2], deep-bore tunneling instead of cut-and-cover to avoid political fighting, and MTA departments wanting their miniature fiefdom dug into the ground at each station [3]. The SAS is a project that should bring great shame to everyone in charge and everyone who stood around in the tunnels getting paid to do nothing.

[1] https://en.wikipedia.org/wiki/Uptown_Hudson_Tubes (tunnel happens to be about a mile and it cost 21 million 1905 dollars)

[2] https://www.nytimes.com/2017/12/28/nyregion/new-york-subway-...

[3] https://pedestrianobservations.com/2023/12/09/the-mta-sticks...