Recently I acquired a size 16 Hamilton 993 s/n 1556972. It is pendant set which, at first, required a good pull. This became more friendly after a clean and oil.

I understand only 2000 of this series was produced. Because it is "pendant set" I believe the watch, although possibly rare, can not be classified as "Railroad Standard" but I may be wrong.

Comments please.

^

The watch in question was made 1921-1924

So the answer is

It was "rail road grade" [RRG], which means the quality was there,

But it was not "rail road approved" [RRA], which means the RR's in that time frame would not have accepted it into service because of 2 reasons;

[A] Only lever-set watches were approved
[B] Only open-faced watches were approved OR
watches that "wound" with the stem at the
12 o'clock position.

The 21J Hamilton 993 pendant-set watch is not a "rare" watch. It is the hunter cased version of the Hamilton 992. It is not as common as the 992. It is uncommon, but it is not scarce.

regards,
bb