This Accutron says Railroad Approved, and it looks like a train ran over it.
Scratches everywhere, and the crown stem is loose to the point of not turning the hands. I'm not nearly competent enought to even try resetting/re-attaching it.
I can find no serial number on the movement, though it does read 2181, which I assume is the model number. Also, at the top of the movement, there is extra-tiny print that reads, "U.S. Pat......." followed by a whole bunch of numbers that I absolutely cannot make out. I think they are actually microscopic, and my electron microscope is in the shop.
The only other type I can find on the movement reads, "U.S.A. Bulova"
The inside case back is stamped "G3595" followed by "3-6" and "Use only genuine Accutron Cell number 218 Install with engraved side down in well"
And that's it. It's pretty beat up, but it's a Bulova.
The G3595 number is the case number. The 3-6 number refers to the month and day of manufacture. The 2181 is the specific caliber/sub caliber of the movement. What you have is a 218 RR Approved Accutron. I seem to remember that Bulova never actually had the 218 movement officially certified by the railroads but I could be wrong about that. Bulova did have the 214 caliber officially certified.