Nice railroad pocket watch, Ball maybe are the most expensive model right now on the market, you can see in ebay. This one i think is from the 1920 50s. Is my opinión because the watch is really new, its look like from this century. The oldest cost much more and they have more value from the start of 1900s. Elgin i think also have ball types, waltham also. The watch is very good.
I agree that this is a very interesting movement. Even searching through a Hamilton information book, it's hard to figure out what it is exactly. We know it's a Hamilton made for, and sold by Ball. It's also one of the top grades that Hamilton ever produced. The configuration of the bridges, bridge model, look like a Hamilton 950B, but I don't see anywhere that this was used for Ball watches. From what I can tell, there may have been a few made, but were basically prototypes. I don't want to get your value hopes up, but it sure looks like a real rarity you have there. And it's in very fine condition.
You might consider going to the NAWCC forum and asking about it in the Ball or Hamilton section. There are a few guys there who are very knowledgeable about these high-grade railroad watches. I'm a bit stumped, aside from the obvious quality and seeming rarity. Good luck.
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