https://watchbase.com/omega/railmaster/2502-52-00

Introduced at BaselWorld 2003, the Aqua Terra Railmaster is a tribute to the Railmaster of the late fifties. The model presented here (ref. 2502.52.00) has a stainless steel case of 41mm and a matching bracelet.

The original OMEGA Railmaster was first launched in 1957 – the same year as the now legendary Speedmaster model – as the successor to a watch created for the British Royal Air Force in 1953. Designed specially for scientists, technicians, electricians and railway workers, or anyone else working in or around powerful electric currents, it had a special double antimagnetic case to protect the watch movement from the harmful effects of these electrical fields. The outside case was made of Staybrite stainless steel, with a polished bevelled bezel, polished solid enveloping lugs, reinforced crystal and a screw-in back with O-ring gasket to ensure water resistance. The inside case consisted of a protective cap, a casing ring and a 1mm thick dial (as opposed to the 0.4mm for a standard dial) made of soft iron, which formed a screen against magnetic fields of over 900 Oersted in any position, as opposed to 60 Oersted for a conventional antimagnetic watch.

The contemporary Railmaster retains the exterior look of the original, with a matt black dial bearing four luminous Arabic numerals at the quarter hours together with luminous triangular hour markers and central Railmaster inscription. The facetted Dauphine-style hands (with arrowhead minute hand) also have luminous inserts, ensuring excellent legibility in all light conditions. A more up-to-date domed, anti-reflective, scratch-resistant sapphire crystal kept in place by the Aqua Terra's simple polished stainless steel bezel rounds off the pure lines of the watch. The interior of the new Railmaster is a different story, however. The original calibre 30SC T4 created in 1955 (a derivative of OMEGA's world-renowned 30mm calibre) is replaced by a new version of OMEGA's revolutionary Co-Axial Escapement movement. The latest incarnation of this movement, OMEGA calibre 2403, displays the hour, minute and central seconds on a sober yet tidy dial. The Co-Axial movement is self-winding and chronometer certified by the COSC (Official Swiss Chronometer Testing Institute). It has a power reserve of 44 hours and an intricate finish of Geneva wave décor and circular graining with gold-plated engravings. The innovative technology of the OMEGA Co-Axial Escapement reduces friction in the watch's drive train and thus offers better long-term accuracy.

The Railmaster models are available only with the new Co-Axial movement and hence only in the 41mm and 38mm case diameters. A choice of steel bracelet with safety clasp and brown or black leather straps with foldover clasp provides for a total of six models in this collection. Like all Aqua Terra models, they are fitted with a screw-in crown and case back that ensure water resistance to 150 metres, the latter fitted with a scratch-resistant sapphire crystal that guarantees a view of the watch's unique movement that will always be perfect.