> Under the project name of Crossrail, the system was approved in 2007, and construction began in 2009. Originally planned to open in 2018, the project was repeatedly delayed [...] The service is named after Queen Elizabeth II, who officially opened the line on 17 May 2022[...].

I wouldn't say thin air, exactly.

>> I wouldn't say thin air, exactly.

Fair but have you seen how long things take in the US? The original proposal for the 2nd ave line was in 1920 and they have only managed to deploy four stops. I read about it in the news when I was in 5th grade and still read about it now, 40yrs later. https://en.wikipedia.org/wiki/Second_Avenue_Subway

Similar for the Hudson tunnel which is supposed to allow commuter trains to function w/o the current madness...