Fun to "normalise" - the UK, for example, has both the recent London underground extensions and the London Sewer projects that have figures on tap for large tunnels + extras.
This specific "tunnel with windows" is $400 m USD quoted in toto for a 675-foot avalanche resistant rock shed.
In Yosemite they're cutting through the edges of hard rock - as opposed to the much softer soils under London and the Thames, and they're making an impact shock resistant structure exposed to daily heating and cooling as opposed to relatively zero shock resistant tunnels with far less of a temperature cycle.
For a Yosemite tunnel the length would be greater and the cutting challenges greater (rock V soil).
Apples, Oranges.
You might be better served looking to European rock shed construction of a similar scale - the civil engineering aspects would be similar.
https://www.flickr.com/photos/tranbc/26942437655
What would an actual tunnel cost in Europe or China?
This specific "tunnel with windows" is $400 m USD quoted in toto for a 675-foot avalanche resistant rock shed.
In Yosemite they're cutting through the edges of hard rock - as opposed to the much softer soils under London and the Thames, and they're making an impact shock resistant structure exposed to daily heating and cooling as opposed to relatively zero shock resistant tunnels with far less of a temperature cycle.
For a Yosemite tunnel the length would be greater and the cutting challenges greater (rock V soil).
Apples, Oranges.
You might be better served looking to European rock shed construction of a similar scale - the civil engineering aspects would be similar.
The environmental consultants will drag this out for a decade if they can.
* (I didn't really laugh, just used the acronym for its disrespectful tone)