Railroad chronometer
Encyclopedia : R : RA : RAI : Railroad chronometer
Railroad chronometers (railroader's watches) were critical to the safe and correct operation of trains in the United States. A system, which relied on accurate timekeeping, called Timetable and Train Order was used to ensure that two trains could not be on the same stretch of track at the same time.
After a serious train accident in 1891 in Ohio, caused by the malfunction of an engineer's watch, the North American railroad industry charged their General Time Inspector Webb C. Ball to establish unified standards for all the watches used by their personnel across the various participating Railroad Companies:
- only American-made watches may be used (depending on availability of spare parts)
- only open-faced dials, with the stem at 12 o’clock
- minimum of 17 functional jewels in the movement, 16 or 18-size only
- maximum variation of 30 seconds (approximately 4 seconds daily) per weekly check
- watch adjusted to five positions (face up, face down, crown up, crown down, or sideways)
- adjusted for severe temperature variance and isochronism (variance in spring tension)
- indication of time with bold legible Hindu-Arabic numerals, outer minute division, second dial, heavy hands,
- lever used to set the time (no risk of having the stem left out, thus inadvertently setting the watch to an erroneous time)
- Breguet balance spring
- micrometer adjustment regulator
- double roller
- steel escape wheel
- anti-magnetic protection (after the advent of diesel locomotives)
- jim-proof
See also
External links
- [Waltham Serial Numbers]
- [Elgin Serial Numbers]
- [Howard Serial Numbers]
- [Just What is a Railroad Watch?]
- [American Watchmakers-Clockmakers Institute]
- [Ball Watch Company]
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