Lovely Hamilton 992B railroad watch. Fresh service.

Terrific railroad watch made by Hamilton Watch Co. in 1944.
The 992B is arguably the best of the railroad watches as it features all of the very latest technology. It was so good that it was in continuous production from 1941 until 1969 when the factory closed, during which time it was entirely unchanged.
Featuring a fully capped Swiss lever escapement with double roller, Sapphire pallets, gold timing screws, and a sprung micro-regulator. The movement also has the "Elinvar" white metal alloy hairspring and associated solid mono-metal balance wheel. Earlier carbon steel hairsprings were found to be susceptible to changes in ambient temperatures which severely affected their timekeeping abilities. A change of 1deg. could cause a watch to run up to 11 seconds fast or slow due to the expansion/ contraction of the metal. To counter this, balance wheels were made of brass bonded to steel and had 2 slits cut in them to effectively produce 2 arms. These 2 arms could expand out or contract in to effectively alter the mass of the wheel thus countering the expansion / contraction of the spring. This was expensive to produce and difficult to set up correctly. The "Elinvar" spring is unaffected by temperature and is also anti-magnetic so solves 2 problems.
This particular watch has just had a full service and is fitted with a new mainspring. Running strong in all positions it is keeping time within + a couple of seconds per day.
The watch is stem wind and lever set (withdraw the small lever by the 1 and rotate the crown to set the time).
Original Hamilton signed gold filled case in super all round condition. Screw on/off front and rear covers, both do so easily and both close down square and tight.
Beautiful unmarked "Montgomery" dial with a very good set of black enamelled hands under a very good acrylic crystal.
Overall a beautiful example of this iconic railroad watch that runs perfectly.