RR Pocket Watch Regulation

[wingman]

I’ve just overhauled a Waltham 18, 17 jewel pocket watch. It is keeping really good time, compared to some of the 5 to 11 jewel movements I’ve done. What would be a normal +/- seconds per day for a Rail Road type pocket watch?

[randy]

From an article attributed to Ed Hahn:
The constant in all of this was that railroad watches needed to maintain a standard of timekeeping of less than 30 seconds of error over a week “.

http://people.timezone.com/library/tmachine/tmachine0007

And keep in mind that it was ( is ) not acceptable for an accurate watch to lose or gain a large amount every day,..IE 10+ one day, and 30- the next, even if it averages out to meet the weekly rate.
Much better to have it gain/lose 4-5 seconds per day, steady. Better example of constant Isochronism.

So how’s it doing ???

Best regards,

Randy

[david pierce]

Wingman,
The standard for railroad watches and certified chronometers in general was + or – two seconds per day or one minute per month in six positions within a given temperature range. Crystal controlled electronic watches can hold the time within 5 seconds per month in any position within a greater temperature range, which is why they overshadowed mechanical watches.
David Pierce

[wingman]

I guess I have a long way to go. It gains about 30 seconds per day.

[Author]

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