Service: Omega Railmaster Aqua Terra 168.1111 calibre 2403A

IMG_6973I like the Railmaster range because of its simplicity and non-fussiness. This one is no exception. Chris sent it in, as it doesn’t keep time very well.

Let’s have a look at the timegrapher…IMG_6974

Ignore the amplitude reading – I haven’t adjusted for the lift angle of 38 degrees yet. But the -41s/day and the patchy graph are for real. Having read George Daniels biography over the holidays, I am sort of curious how he would interpret this… He claimed that his watches could go 15 years without a service and keep their accuracy, and weren’t in need of lubrication. Surely his watches had a balance, jewels, jewel caps, etc. and needed oil in all those vital places.

I do of course understand his argument about the friction between the escape wheel and the pallet stones, and why the co-axial escapement is better in that respect. But all the rest is just a normal mechanical watch, with the same need for lubrication and cleanliness.IMG_6981

The 2403A is a variation of the 2500A – just without the date.IMG_6985

The balance roller is also different, as the power that is transmitted to the balance is transmitted in one direction by the impulse pin, but in the other direction by a jewel that looks very much like a pallet stone.IMG_6987The double escape wheel and the pallet fork of the co-axial escapement.IMG_6989

The wheel at the bottom drives the two co-axial escape wheels.IMG_6994

All components go into the cleaning machine.IMG_7098

I start off with the usual new mainspring.IMG_7099

Then I put the balance jewels in.IMG_7102

The base movement is back together and ticking. The teeth of the lower escape wheel the accelerate the jewel on the escape wheel get a tiny tiny drop of oil each.IMG_7103

Now let’s see what the timegrapher says.IMG_7104

This will need some adjusting – done on two screws on the balance.IMG_7105

And we’re there. Good amplitude, but not a completely flat beat rate. IMG_7106

The bottom plate back together.IMG_7107

I put together the auto winder assembly.IMG_7110

Now I can case the movement.IMG_7113Back in business and ticking happily.

So – does the co-axial movement need less servicing? In principal yes, but practically, no.

Does it keep better accuracy over time? Not in this case 😉

Is it more accurate than the non-co-axial version? Not really.

But, it’s a technically interesting movement, and I can see the theoretical advantage of the co-axial escapement. Got to get my hands on an 8500 😉



16 thoughts on “Service: Omega Railmaster Aqua Terra 168.1111 calibre 2403A

  1. Hello!
    I found this co-axial service and I have a question about oiling it – how do you do it? Or could you recommend an article or something about this?

    Thank you,

  2. As a no-date kinda guy, this watch is beautiful. I have a calendar on my phone and rarely need to check the date more than once a day.

    My curiosity is, was there any reason for the service? (other than the obvious bad keeping of time) Was it dropped or exposed to shock? I’m curious as Omega makes a lot of claims about the coaxial movements and service intervals.

  3. that’s quite poor for such a new watch to need attention.

    Christian, I did read in an article about the co-axial escapement that although Daniels specified no oil on the escape wheel due to the use of radial friction as opposed to sliding friction in the traditional escapement, that Omega went ahead and oiled the escape wheel anyway – i’m not sure if Daniels knew about this. The writer of the article (an experienced watchmaker) dismantled a brand new co-axial and found oil in quite a few places where none was supposed to be required. Omega being cautious perhaps?

    • According to his autobiography, he knew about the oiling, as there were issues with the teeth of the escape wheel getting slightly damaged.
      My point is really that there are lots of factors why mechanical watches aren’t completely accurate and require service – the co-axial escapement only addresses one of those points.

      • Interesting, I wasn’t sure if he knew.
        I’d agree, after all, as you say the rest of the watch is still a traditional mechanical movement with all the usual parts requiring oiling.

        I was surprised to see how much more complex the co-axial escapement was than the swiss lever type. From the end users point of view, it is difficult to see the advantage of the co-axial escapement. It still requires periodic servicing, but is significantly more complex.

        Given that the lever escapement is so well proven and reliable, to me it feels like a solution to a non existant problem.

        • I consider the co-axial escapement to be more of a marketing thing. It enabled Omega to move to in-house movements and raise prices (and probably margins as well).
          I think that, in some ways, the Sistem51 can actually be considered the more significant innovation. I’m even considering getting one for those moments when I want to spare my Speedmaster.

  4. So, do we know how long this one had been without service? I guess not 15 years 😉

    I do like the Railmaster design, but always wondered why they don’t have date displays… it is hardly an extravagance!

      • I can’t read the date without my glasses so it’s not an issue for me 🙂

        As Christian says the watch is only 5 years old but it has always lost 20sec or so a day. So I rather suspect that the result Christian shows straight after the rebuild is how it came out of the factory. Yes, I probably should have asked for it to be put right at the beginning but handing it over to a guy in a high street shop and not knowing where it was going would be too stressful for me!

        Top job done by Christian 🙂

        • That’s a bit odd. I thought all co-axial movements were COSC chronometer certified? If this watch had been -20 seconds from initial purchase – methinks something is rotten in Denmark.

          • The certification is done on the movement before being cased. Best guess is that something happened to it during assembly or during transport.
            Too bad it was not reported earlier. Omega would have serviced this under their warranty.

          • Yes, this definitely isn’t normal. Usually, a new Omega performs as it should.
            And the problem would surely have been sorted if the dealer had been made aware of it. Definitely a fluke.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.