1939 992E Elinvar Model 10 Railroad Watch

No Hamilton collection would be complete without a 16 Size Railroad Watch.   After all, Hamilton Watch Company was "the watch of railroad accuracy".  In fact, you could build yourself quite the collection of pocket watches by just trying to find all the railroad-approved movement calibers that Hamilton produced.  It's a surprising variety in 16 Size and 18 Size models.

In order to be railroad approved, a watch had to meet a variety or requirements but the requirements also evolved over time and could vary.

Core Technical Specifications

Watches had to be open-faced designs.  So side-winding hunter-case pocket watches were prohibited.  The winding stem had to be positioned at the 12 o'clock position.

The size was limited to 16 or 18 size movements.  Anything less than 16 size was prohibited.

The winding stem had to be positioned at the 12 o'clock position.

The jewel count varied the most over time and rail line.  For the most part, 21 jewels was the cutoff but depending on the period and rail line it could have been as few as 17.

The setting mechanism had to be lever-set.  This requires the bezel to be removed in order to set the time, thus the watch couldn't be accidentally be set to an incorrect time.

The number of adjusted were set to at least 5 positions that a watch would typically be carried in... face up, face down, crown up, crown left, crown right) and adjusted for temperature variations and isochronism (meaning the accuracy didn't vary based on how much the mainspring was wound.

In addition, the balance required a double-roller balance and a steel escape wheel with a micrometric regulator.

The dial was required to be plain white enamel with bold Arabic numerals.  Roman numerals were prohibited after the 1890s.

The hands had to be black or blue spade style.

From an accuracy standpoint, the movement had to maintain and accuracy of within 30 seconds per week.

Railroad watches were subjected to inspection by certified watchmakers on a regular frequency, depending on the line.  Railroad watches were required to be synchronized with a railroad clock daily.

I find these requirements to be fascinating and when you consider the number of rail lines, trains, and supporting personnel, it was a staggering achievement to maintain this standard for so many years and decades.

For a long time the two principle railroad movements were the 16 size 992 and 950 movements.  The 940 18 size movements was also prominent.  You could go even fancier but those three were really the starting point that met all of the requirements above.

In 1934 Hamilton introduced a new hairspring material, Elinvar, that improved their timekeeping even further.  The 992 and 950 were upgraded with Elinvar and resulted in the 992E and 950E movements.  

Their run was somewhat short lived, as both designs would be improved upon again and replaced in 1940 by the 992B and 950B.  Those movements would continue to be produced through 1969.

The 1934 catalog introduced the new 992 Elinvar design.  The 992 features 21 jewels and a solid gold center wheel.  It was offered in several cases with varied dial designs.

Not much changed by 1939, other than the color of the catalog and models shown.  The same Model 2 was shown as well a the Model 10.

Both the Model 2 and Model 10 could be referred to as "bar over crown".  The style of the pendant and the bezel details differed.  The bar over crown design is a sure sign the watch is lever-set, as the crown cannot be pulled out.

My project watch is exactly what was shown in the catalog... it's a Model No. 10 with an HG dial (heavy gothic) and heavy spade hands.

The case back shows lots of wear but nothing too distracting.  The back screws on and off and I find the best way to do it is to hold the watch between your hands and use the friction of your palms to twist the back (or front) off.  Once it's free, your finger tips can take over.  Putting the back or bezel back on requires extra care to make sure you don't cross thread it and put it on crooked.

The 992E looks like any garden variety 992 produced in the 30 years prior.  There are two clues its not a basic 992... first, there's the monometallic balance (more on that in a bit) and the word ELINVAR is stamped on the pallet bridge.  You can see it peaking out in the photo below.

With the bezel unscrewed and removed, you can see the tip of the setting lever at the 6 minute mark.  You slide this lever out with your fingernail and then can set the time with the crown.  Slide it back in and the watch is in the winding position.

With the dial removed, you can see how the setting lever operates.  It's a very clean, simple design.

The monometallic balance has no gaps in the balance wheel.  If you look at the earlier balance design, there is a gap in the wheel at the end of each arm.  This allowed the wheel to expand or contract with temperature and slow or speed up the watch accordingly.  With the introduction of Elinvar, the balance wheel changed.  You'll see the same difference with the 987 movement when the change from the 987F to the 987E was made in 1934.

With the balance and balance cock out of the way, you can clearly see the ELINVAR stamp on the pallet bridge.  You can also see one of the 21 jewels is a cap jewel protecting the end of the pallet fork pivot.

With the bridges removed, you can see the solid gold center wheel is a different color than the other train wheels.  The escape wheel is steel - also a railroad requirement.

Everything is cleaned and dried.  This movement takes up a lot more space than the typical wristwatch movement does.

At this point I have the movement 99% complete.  I just need to add the balance.  First, I will install the movement in the case and use the crown to wind up the mainspring.  With power in the mainspring, the movement will come to life once the balance is in the correct place.

Seeing a watch movement come back to life never gets old.  It's such a rewarding feeling to see everything come back together.  Now I will put it on the timer and see how well it's running.

Not too bad at all... I'll let it run for a little while before I fine tune the timing.

From there it's smooth sailing.  I just have to reinstall the dial, etc. and put the assembly back into the freshly cleaned case.  It's noticeably brighter and shinier now.  Too bad I have to cover it up with the back cover.

The finished project looks great.  This is such a nice watch.  I actually started my watch collecting by focusing on project watches.  Then I realized Hamilton made wrist watches too.  I still have a decent collection of pocket watches but if I were to start over, my advice to myself would be to focus solely on movements with 19 jewels or more.  The collection would be smaller, but it would consist of the most exquisite movements Hamilton made.  It would definitely include a 992E.