The first number is the Lima drawing number the second number after the discription is the Lima pattern number. More info about the Shay Project can be found at www.7-8ths.info
look for the Shay Project in live steam locomotives.
The drawings are in a series of articles in "Steam in the Garden". All the drawings needed to construct a 10 ton 2-6"x10" Shay have been redrawn from original Lima drawings printed in 7/8ths scale with full size dimensions. The plans can be used to construct a Shay in any scale including full size.