Omega
Omega Railmaster Co-Axial Master Chronometer 40 220.10.40.20.06.001
The Omega Railmaster Co-Axial Master Chronometer 40 (reference 220.10.40.20.06.001) is a 40 mm stainless steel watch with a grey dial.
Specifications
Case
- Reference
- 220.10.40.20.06.001
- Collection
- Railmaster
- Case size
- 40 mm
- Case material
- Stainless steel
Dial and bezel
- Dial
- Grey
Dial versions
This reference was made with these dials and finishes.
220.10.40.20.06.001 Grey
Grey
How it compares within the Railmaster family
Side by side with other references in the same collection, from the catalog.
| Reference | Size | Material | Dial | Caliber | Years |
|---|---|---|---|---|---|
| 220.10.40.20.06.001 (This watch) | 40 mm | Stainless steel | Grey | — | — |
| 220.10.38.20.01.002 | 38 mm | Stainless steel | Black | 8806 | 2017– |
| 220.10.40.20.01.001 | 40 mm | Stainless steel | Grey | 8806 | 2017– |
| 220.10.40.20.03.001 | 40 mm | Stainless steel | Blue | 8806 | — |
| 220.12.40.20.03.001 | 40 mm | Stainless steel | Blue | 8806 | — |
| 235.10.38.20.06.001 | 38 mm | Stainless steel | Grey gradient | 8806 | 2025– |
| 235.10.38.20.13.001 | 38 mm | Stainless steel | — | — | — |
| 235.12.38.20.06.001 | 38 mm | Stainless steel | Grey gradient | — | — |
| 2503.52.00 | 39.2 mm | Stainless steel | Black | 2500 | — |
About the Railmaster family
The Railmaster was introduced in 1957 together with the Speedmaster and Seamaster 300 as part of Omega's trio of professional watches. It was built for people working near strong magnetic fields, such as railway workers and scientists, with a soft-iron inner case to protect the movement.
Omega revived the name in the 2000s with Co-Axial models and again in 2017, when a 40 mm Railmaster with the anti-magnetic Master Chronometer caliber 8806 brought back the simple vintage look with a textured dial. Later references in the catalog include smaller 38 mm versions. Dealers tell versions apart by size, dial texture and bracelet or strap.
Quick answers
- What size is the Omega Railmaster Co-Axial Master Chronometer 40 220.10.40.20.06.001?
- The Omega Railmaster Co-Axial Master Chronometer 40 220.10.40.20.06.001 has a 40 mm case.
- What is the Omega Railmaster Co-Axial Master Chronometer 40 220.10.40.20.06.001 made of?
- The case is stainless steel.
Catalog facts checked October 2026.