I think we have a semantics problem here. By "running condition" do you mean "able to run" or "unaltered". A locomotive underwater since 1850 is not in running condition but may be unaltered.

The 1858 date for the Boston & Providence "Daniel Nason" is wrong and should be 1862. When it was "backdated" for the 1893 world's fair it was given a steam dome cover from the only 1858 loco built by the B&P, along with its builder's plate.

The back dating of locomotives to make them more "historic" has bedeveled researchers for over a century.

I can only speak for myself but I'd rather see the Inyo at Nevada State in it's backdated appearance burning wood. To take it away from rail preservation I'd rather see the Rosa Parks Bus the way Rosa Parks would have seen it, and not the way it was retired.

This is what I wrote about the 1858 plate on the Daniel Nason in my article about it in Railroad History #218 (Spring-Summer 2018), a few copies of which may be available at rlhs.org under back issue sales. “The builder’s plate now on the Daniel Nason bears the date 1858, but the locomotive was listed in the roster as #17, which would place its completion in 1863 and is listed in rosters with that date. It is thought that the 1858 plate came from the Roxbury, the only locomotive built by the company shop in 1858. It is possible that the entire steam dome casing from the Roxbury was in better condition and moved to the Daniel Nason, 1858 builder’s plate and all, instead of just the plate itself.”