Some of the links and information I turned up on X-12 in my research.

http://atomic-skies.blogspot.com/2012/07/to-peoria-by-atom.html

https://io9.gizmodo.com/the-days-of-atomic-locomotives-in-america-1564623650

http://brainmindinstrev.blogspot.com/2012/03/project-x-12-borsts-imaginary-nuclear.html

The X-12 in 3D rendition for train simulation program.

https://steamcommunity.com/sharedfiles/filedetails/?id=948029446

Version of X-12 Union Pacific had interest in.

http://www.iridetheharlemline.com/2014/04/11/jets-and-atoms-powering-bizarre-trains/

Feasibility study of atomic locomotive.

https://babel.hathitrust.org/cgi/pt?id=mdp.39015020157130;view=1up;seq=5

Popular science article on X-12.

https://books.google.com/books?id=xyADAAAAMBAJ&lpg=RA1-PA37&ots=XnnK1BcxjR&dq=%22popular+science%22+x-12+1954&pg=RA1-PA37&hl=en#v=onepage&q&f=false

X-12 would have most closely sounded like this steam turbine power plant on board a ship. https://www.youtube.com/watch?v=qqe43wSDfiw

This is just for pure fun and speculation on how something like this could have been preserved possibly?

Robert

Found out about this train only a few years ago while looking at a old Life magazine. Pretty cool concept locomotive, and would be neat to have one in HO scale. When I toured Handford, Washington about 10 years ago they had a large pit that they were putting severed submarine sections into. The severed part held the reactor. They said nearly all the nuclear ships and submarines have this compartment cut out and buried with the reactor (photos here) http://navy.memorieshop.com/Subs/Tunny/ ... actor.html

Because of this preserving future nuclear ships or submarines is very unlikely unless the cut out portion is replaced. I imagine had this locomotive become a reality it would be a important historical artifact for the World. If it was preserved, then the reactor compartment would have been cut out and removed and replaced with a empty room. I am sure it would have ended up in the Smithsonian as a testament to the advancement of technology.

This locomotive reminded me of the never produced ACE 3000 which was also a interesting locomotive.

Tom, I spoke with James from JamesTrainParts a while ago. He was willing to build a HO model on commission. Price quoted would have been around $1500. I was interested in the UPRR version from the Life Magazine. The project would have started with a pair of Life Life E7 shells and used 3D Printed parts and pieces along with polystyrene plastic. The condenser car would have been all 3D Printed I believe.

Robert

Interesting about Hannaford. I think subs are defueled at Portsmouth Naval Shipyard, then towed to Washington state. The Navy maintains rail access to Portsmouth to ship out the fuel.
I'm old enough to remember dreams of nuke locomotives. Trains magazine may have had an article about them too.