Omega · Railmaster
Strap for Seamaster Aqua Terra 150M Co-Axial 39.2 Railmaster Yellow Gold / Black Alligator
Takes 20 mm straps. Verified lug width, the straps that fit this model, and answers to the most common questions.
Lug width
Recommended spring bar
Straps for the Railmaster 2603.52.31 (aka: 26035231)
Selected for the 20 mm lug width · workshop selection
Black Alligator Strap with Light Blue Edges€149
Red Alligator Strap Water Resistant€195
Green Rubberized Alligator Strap with Ecru Tribal Stitching€149
Hammered Calfskin Strap Light Blue€98
Vintage Olive Green Calf Leather Watch Strap€80
The Railmaster 2603.52.31 (aka: 26035231), seen from the bench
Frequently asked questions
What is the lug width of the Omega Railmaster 2603.52.31?
The Railmaster 2603.52.31 features a <a href="/pages/termine-glossario/misura-ansa">lug width</a> of 20 mm. This specification is model-specific and corresponds to the internal distance between the two lugs of the case. Ensure that your replacement strap respects this dimension to guarantee precise and secure fit.
Which strap pairs best with the Railmaster in yellow gold?
For the Railmaster 2603.52.31 in yellow gold, we recommend <a href="/pages/termine-glossario/alligatore">alligator</a> in cognac or dark brown tones, which create a natural aesthetic harmony with the metal. <a href="/pages/termine-glossario/shell-cordovan">Shell cordovan</a> is the connoisseur's choice: it develops a deep patina over time, in perfect dialogue with the aging of gold. For minimal daily use, black or anthracite grey calf maintains sobriety without detracting from the case design.
How do you change the strap on the Omega Railmaster 2603.52.31?
The change occurs by removing the spring bars that connect the strap to the case lugs. Use a dedicated tool (spring bar tool) to depress the pin and slide it out of the lug. Repeat with the second pin, remove the old strap, align the holes of the new strap with the lugs, reinsert the pins until the click closes. Final checks: the strap must not rotate around the lugs.
Can I use an aftermarket strap on my Railmaster 2603.52.31?
Absolutely yes. The important thing is that the strap respects the <a href="/pages/termine-glossario/misura-ansa">lug width</a> of 20 mm and that the lugs are compatible with standard spring bars. High-quality artisanal straps (alligator, calf, cordovan with vegetable tanning) are not only compatible, but amplify the vintage-elegant character of the Railmaster, offering aesthetic alternatives that Omega does not provide.
How long does a leather strap last on the Railmaster 2603.52.31?
Durability depends on use intensity, climate, and the leather chosen. A high-quality <a href="/pages/termine-glossario/alligatore">alligator</a> or calf, worn 5-6 days a week in temperate climate, lasts 4-6 years before requiring replacement for aesthetic wear. <a href="/pages/termine-glossario/shell-cordovan">Shell cordovan</a> with <a href="/pages/termine-glossario/concia-vegetale">vegetable tanning</a> can exceed 8 years, thanks to dense fibers and natural resistance. Regular maintenance (periodic cleaning, discrete conditioning) significantly extends useful life.
The next step
The right strap isn't chosen. It is built, together.
From the atelier appointment to delivery, every step is made for those who know that things done well take time. Rare leathers, one piece at a time, eighteen months of warranty.
Request an appointment →Casati Milano · Via XX Settembre 15, Milan · by appointment only