In the 1927 catalog you can find for the first time a model called "Eisenbahneruhr" "Railway watch"
Special was the inner circle number 13 to 24 and the larger 20 1/2''' case.
Movement J33b
Junhans catalog 1934 text:
Railway watch, white metal, polished or engine turned, bass., breguet compensating hait spring, enamel dial.
Movement J47b, case size 20'''
The "Railway watch", "Eisenbahneruhr" was still in the catalog 1949 with the movement J47b, but only with a
larger 20''' white dial with radium numbers 1 to 12 and small 13 - 24 numbers as a outer circle.