Editing Railroad chronometer (section)

==Manufacturers==
The [[Waltham Watch Company]] and the [[Elgin Watch Company]] were both used as early as the 1860s and 1870s <ref>National Association of Watch and Clock Collectors [http://mb.nawcc.org/showwiki.php?title=Waltham+Watches "Waltham Watches"]</ref><ref>The Elgin Watch Collectors Site [http://elginwatches.org/index.html "Elgin Watches"] {{Webarchive|url=https://web.archive.org/web/20100819101949/http://elginwatches.org/index.html |date=2010-08-19 }}</ref> as railroad standard watches.  Later, [[Hamilton Watch Company]], [[Illinois Watch Company]] and many of the other American watch manufacturers all produced railroad-grade watches like the [[Ball Watch Company]].

The [[Time signal|Time Signal]] Service of the [[United States Naval Observatory]] was used to ensure accuracy of railroad chronometers and schedule American rail transport.<ref>U.S. Naval Observatory [http://tycho.usno.navy.mil/history.html "History"] {{Webarchive|url=https://web.archive.org/web/20171219093942/http://tycho.usno.navy.mil/history.html |date=2017-12-19 }}</ref>