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The Encyclopedia of Horology

Movement record · United States

Hamilton 992B

Verified

Three-quarter plate nickel movement with damascened finish, motor barrel and micrometric regulator; designed specifically to satisfy railway time-service requirements.

Technical specifications

Diameter
16 size (approx. 43.1 mm)
Height
Approx. 5.8 mm
Jewels
21
Frequency
18,000 vph (2.5 Hz)
Power reserve
Approx. 40 hours
Winding
Stem wind (pendant set variants exist)
Setting
Lever set
Escapement
Swiss lever, exposed pallets
Balance
Elinvar Extra hairspring with monometallic balance
Complications
Subsidiary seconds

Identification features

  • '992B' grade marking on the barrel bridge with 'Railway Special' on many examples
  • Elinvar Extra marking on the balance cock area
  • Lever set visible after removing the bezel

Known variants

  • Early 992B with ionic dial
  • Late production with melamine dial

Servicing notes

Parts availability is good relative to other American grades. The motor barrel requires correct disassembly; do not force the arbor.

General guidance only. Antique movements should be serviced by a qualified watchmaker.

Historical significance

Generally regarded as the culmination of American railroad-grade production and a benchmark for studying positional adjustment.

Photographs

Hamilton Watch Complex
Hamilton Watch Complex — Niagara, CC BY-SA 3.0. Wikimedia Commons file page
Hamilton Watch Complex, 1963 wing
Hamilton Watch Complex, 1963 wing — Niagara, CC BY-SA 3.0. Wikimedia Commons file page
Hamilton Watch Complex, east clock tower
Hamilton Watch Complex, east clock tower — Niagara, CC BY-SA 3.0. Wikimedia Commons file page

Photographs are illustrative examples of the type, not necessarily the exact object described. Verify details against the source file page.

Sources & references

  1. Hamilton Watch Company service literature
  2. NAWCC Bulletin

Where sources disagree, the disagreement is stated rather than resolved silently.