Re: Railmaster Automatic Chronometer
The following quote is from another web site describing the 1957 introduction of Omega "master" watches:
"The goal of Omega factory was offering 3 brand new technical - "master" - watches to the market. The Speed was intended for car racers or sportive people in need of measuring short periods of time (Stop watch functions), the Sea was designed for professional divers – with its improved waterproofing – while the Rail for engineers who were working in strong magnetic field areas (double housing case, and specially designed dial resisting to around 1000 Gauss, say 0.1 Tesla)."