As far as I know, Crossrail is the name of the project whilst the Elizabeth line is the name of the actual line. The Elizabeth line seems to be not quite an extension of the underground.<p>This video clears it up somewhat [1].<p>[1] <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=XaBBg6Cyv9Q" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=XaBBg6Cyv9Q</a>