The rebuilding of extinct steam locomotives are a fairly new concept to the steam preservation world. With British railway building a LNER Peppercorn Class A1 60163 AKA Tornado built between 1994 to 2008. We can see rail fans following in British Railways footstep and build other extinct locomotives. Below is a list of locomotive being built.
http://www.lms-patriot.org.uk/loco-progress (LMS PATRIOT)
https://www.theclanproject.org/ (BR Standard Class 6)
https://www.p2steam.com/ (P2 2-8-2 Mikado)
http://www.cockothenorth.co.uk/ (Streamlined P2 2-8-2 Mikado)
http://www.82045.org.uk/ (BR 3MT 2‑6‑2 82000)
Now all the above are British. The only American Locomotive Trust is the T1 Trust.
https://prrt1steamlocomotivetrust.org/index.php (PRR T-1)
But that's not the point. The point is there have been several rumors that the T-1 is being built to beat the A4 Mallards Steam Speed record of 126 MPH . But, is that really a good idea? Is it really ethical to rewrite history of the in the 21st century? In my opinion build the T-1 BUT DONT try to beat the world steam speed record set by the A4. Tell me your thoughts.
YouTube video about T-1 beating steam speed record: https://www.youtube.com/watch?v=RSGyVkeDGg4
