Talk:Railroad chronometer

Hamilton 956
Hamilton 956 was introduced around 1915. 1,500 were produced for the Railroad trade. Its a great example of a 17 jewel railroad watch released before 21 jewel or 23 jewel RR Watches became standard. Not accepted by the Watch collecting hobby as a true railroad watch, because after the first 1,500 were produced, Hamilton changed it from a lever-set to a stem-set watch, and mass-produced it for general release to the public. Some accept the theory that it was a railroad watch for the smaller Railroads. The 956 movements were stamped with the 956 model number onto the movement plate, typical of railroad watches. Not until decades later, as exhibited on Omega wristwatch movements, for example, did it become standard practice to put model numbers on all movements. Marc S. 206.192.35.125 (talk) 18:58, 23 September 2015 (UTC)

Article title
Was the term "railroad chronometer" ever in widespread use in the USA? I don't believe so, but I'm by no means certain. The term "standard watch" which the article introduction mentions certainly was used, as was the plainer "railroad watch."

There was one specific watch (Keystone/Howard series 11, made c. 1910-1920) that was called the "Railroad Chronometer," but I think that's a product or brand name and not one for the category. 38.99.125.4 (talk) 19:34, 19 October 2015 (UTC)

--- I added the globalise / globalize template because I agree this problem was likely to have occurred in European railway networks of the 19th century too. These were as dense, or denser than, US 'railroads' but were there equivalent, or tighter, standards? It would be very interesting to know. For instance a crash between Brighton and London in (approx) 1870 was attributed to timekeeping error IIRC. C_j. — Preceding unsigned comment added by 2.101.214.27 (talk) 21:56, 17 May 2023 (UTC)

Chronometers versus watches
This article seems to ignore the difference between chronometers (highly accurate clocks weighing several pounds) and pocket watches. For example, the article claims that railroad-grade pocket watches of the late 19th century were required to keep time with a "maximum variation of 30 seconds (approximately 4 seconds daily) per weekly check." This is highly unlikely, and probably physically impossible. Even very expensive full-size mechanical clocks (like the kind used on ships' bridges in WWII, still sold new for about $2,000) gain or lose up to 60 seconds per week. Pocket watches are less accurate. Modern 17-jewel mechanical pocket watches generally gain/lose about 40 seconds per day. Therefore, it is far more likely that a high-quality pocket watch of the late 19th century would gain/lose 30 seconds per *day* not per week. — Preceding unsigned comment added by Xanthis2 (talk • contribs) 22:22, 1 November 2021 (UTC)