I have been looking at the watches on e-Bay. It strikes me that there is more than one design of the 992B movement. How many were there over it's lifetime? Also how many different dials were made for it including enamel and melamine?

There were 4 different signatures on the 992B movement.

Dials: All Railway Specials

121 RWS DS HG Melamine
151 RWS SS Numerical Melamine
168 RWS SS Melamine
379 RWS DS Melamine
536 RWS DS HG Enamel
537 RWS DS BM Numerical Montgomery Enamel

Miss any Terry?

Rob

good job Rob!

There was also a dial 080, which i believe to be a single sunk 'porcelain' dial

The numbers Rob has listed came from material catalogs or other places. There is a time frame where the dials are named instead of numbered.

And the four movement sigantures is the current total, excluding the movements marked US ARMY and US GOVT.

Narrowing down the change over points all the time, and also finding overlaps....