Yellow gold filled railroad watch made for Ball by Hamilton, 16 size, serial number B631071, circa late 1920s. Clean porcelain dial with black Arabic numerals, minute markers, subsidiary constant seconds register signed Trademark Official RR Standard Ball Watch Co. Cleveland. Ball model screw back case with stirrup bow, brassing around the back outer edge. Fully signed 21 jewel movement with 5 adjustments and sapphire pallets, probably a Hamilton 999 movement in very good condition.