Omega Aqua Terra Railmaster 2504.52

Omega Aqua Terra Railmaster is one of the first Omega Railmaster reissues from the early 00s. The watch features no-date 2403 movement and 3-6-9 dial present in the earlier references. The thing to note is that the Aqua Terra Railmaster is not an antimagnetic watch in the spirit of Eberhard Scientigraph, Rolex Milgaus, IWC Ingeniur or the original Omega Railmaster. Instead, as part of the Aqua Terra lineup, the 2504.52 Railmaster was perhaps meant to compete with Rolex Explorer.

The Aqua Terra Railmasters are defined by no date 3-6-9 dial, painted super luminova plots, screwdown crown and co-axial movement. The watches offer 150m water resistance making them durable companions to office dwellers, commuters and downtown mall spelunkers .

Basic Information

Movement2403 (ETA 2892-A2)
Lug to lug44mm
Lug width19mm
MaterialStainless Stee
Water Resistance150m


The 36mm Aqua Terra Railmaster was released during time when Omega lineup was based on the more is more principle. Similarly to the Planet Oceans, the Aqua Terra Railmaster was released in multiple configurations from 36mm to 49mm. Of these, the 39mm variant is the most popular and easily found. There has been discussion that the 41mm would be the rarest, but they seem to be available at any given moment unlike the 2504.52 or 2804.52 which show up few times a year.

ReferenceSizeLug WidthDetails
2504.5236mm19mm1575/899 bracelet
2804.5236mm19mmLeather strap
2503.5239mm20mm1574/898 bracelet
2803.5239mm20mmLeather strap
2103.5239mm20mmYellow gold, yellow gold bracelet
2603.52.3739mm20mmYellow gold, brown leather strap
2603.52.3139mm20mmYellow gold, black leather strap
2502.5241mm21mm1573/887 bracelet
2802.5241mm21mmLeather strap
2806.52.3749mm24mmLeather strap, Manual wound
49mm24mmRose gold, leather strap, manual wound
49mm24mmWhite gold, leather strap, manual wound
Aqua Terra Railmaster Chronometer references

If you’re “A Big Watch Guy” the 49mm Railmaster could be a good alternative IWC Big Pilot. In a way, the most interesting reference is the 18k 2103.52 with the 18k gold bracelet. I don’t fancy owning one, but it’d be amazing to see it in person one day.


The bracelet features integrated clasp without any micro adjustments. The bracelet is a typical pin & collar bracelet of the era. The bracelet is robust and serviceable as pins take most of the wear and they can be replaced during the service. The downside is that for amateurs the bracelets can be difficult to adjust and it is easy to bend pins and lose collars.

Braclet / EndlinkLug WidthBuckle
1575/899 19mm16mm
1574/898 20mm17mm
1573/887 21mm18mm (?)
Aqua Terra Railmaster Chronometer bracelets

For those who suffer from swelling, the bracelet may not be optimal as there is no micro-adjustment. Another issue is getting it properly fit as the size is controlled with half-links. As for the 2504.52, the 19mm to 16mm taper is proportioned and relatively standard and the bracelet is very comfortable.

For perfectionists and people who suffer from OCD, the bracelet design makes it nearly impossible to center the hidden clasp. This may be a serious downside depending on the mental condition of the watch enthusiast.


Field watches and nato straps go together like salt and pepper. The 2504.52 is no exception. For people who can’t live with a cheeky springbar, the 19mm lug width may be difficult to digest. However, if you take the peeking spring bar as a stylistic element, the Railmaster Chronometer can be worn with just about any 18mm Nato.

Another option is leather. I have yet to purchase a 16mm Omega Deployant clasp, but I’m planning to do so and get a quality leather, sailcloth and canvas for change.

Dial and Hands

The 3-6-9 dial is a throwback to the original Railmaster from 1950s. Aside from green super luminova, the Railmaster Chronometer has more text on the dial. The defining feature of the no-date dial is symmetry and simplicity. The dial of the 2504.52 is about the same size as 2201.50. This makes it a very good companion to the 42mm Planet Ocean of the same time. The 2503.52 has a slightly larger dial than 2201.50, which may look out of place next to such imposing dive watch.

With the hands, there comes a major difference to the original railmaster. The original Railmaster has Ranchero style hands with Arrow hour-hand whereas the Aqua Terra Railmaster has a regular hour hand and arrow minute hand. This difference is inherited from the Aqua Terra line-up, which still uses this configuration even today.


The watch is powered by the 2403 movement, which is a no date version of the cal 2500. Just like the cal 2500, due to the early issues with the co-axial escapement, the movement received an upgrade with lower beat rate. It is not a big surprise to anyone that the movement feels and winds exactly like its date sibling, the cal 2500, but without the date adjustment. Crown action is robust and very tool-watchey. The see-through case back is a nice touch and the rhodium plated movement is beautiful.

The 2504.52 is a late addition to the family. The 39mm and the 41mm versions can be found with both movement types 2403A and 2403B. However, all of the examples of the 2504.52 that I have tried to buy have been with 2403B movement with 84xxxx serial. If somebody knows whether the 36mm Railmaster came with a 2403A, I’d be interested to know and update this post.

2504.52 Seen in Wild

ReferenceSerialMovementSoldSeen onPrice
2805.528472403BChrono24 Dec 2022 (Norway)3600 EUR
2804.52??????Chrono24 Aug 2022 (Germany)3200 EUR
2504.5284780XXX??Chrono24 Aug 2022 (USA)4 704 EUR
2504.5284644XXX??Chrono24 Aug 2022 (USA)4805 EUR
May 2022
4200 USD
2504.5284762XXX2403B7th of April 2011
r/watchexchange, May 2022
5000 USD
2504.5284762XXX2403B7th of April 2011Yahoo Auctions Japan 16/3/2022440 000 JPY
2504.5281712850????Chrono24, Germany, 14/11/20213750 EUR
2504.5281699609??2007.1.4Yahoo Auctions Japan 17/10/2021220 000 JPY
2504.52?????Chrono24, Czech Republic4300 EUR
2504.5284699791??October 26th, 2010Chrono24, USA 24/7/20214999 USD
2504.52?????Chrono24, Singapore 11/8/20213755 USD
2504.52846979532403B2012Chrono24, Usa 6/8/20214513€
2504.5284643XXX (mine)2403BYahoo Auctions Japan 25/7/2021300000 JPY
2504.52UnknownUnknownChrono24 (Japan) 2735€
2504.528478XXXX2403BWatchuseek 30/10/20204250 USD
2504.5281699XXX2403BOmegaforums 30/8/20204150 USD
Known 2504.52 serials


The 36mm Railmaster Chronometer is an interesting watch:

  • It can be used to make a poor man’s late 00s trilogy.
  • It is an obscure alternative to Rolex Explorer.
  • It is rare and worth collecting / hunting.

Personally, I find the early co-axial movements interesting and the looks of 2504.52 appealing. It makes an excellent everyday watch and a perfect companion to the 2201.50, which I also like.

In case of errors, please reach me out with DMs. I’d like to correct them.

4 responses to “Omega Aqua Terra Railmaster 2504.52”

  1. Hello, I have bought this “obscure” alternative to the explorer in aug 2022 from Germany.
    the serial is 8171xxxx and has a 2403B movement…I find this watch at least as interesting as the 114270. Best regards


    • Thanks for the input and the information. This watch is very interesting and I still enjoy trying to spot it for sale to figure out if it ever was produced with 2403A.


  2. I don’t think it was ever released as a 2403A. The A version Co-Axial calibres were part of the initial run of DeVille Co-Ax’s that were first released in the very late ’90s.
    I could be wrong, but I think by the time the Raily was released in the first years of this century, the bugs in the Cal 25XX Co-Axial movements were being ironed out. I had a Co-Ax AquaTerra (36mm) from 2005 and that housed a 2500C.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: