I look at the Official Guide from a production stand point. It is an amazing amount of complex type setting that involved many people using Monotype type setting and hand work putting the tables together. From the made up pages of type, electrotypes were made of each page which were then put on a printing press for the final printing. The entire book was quite likely kept "standing" which meant that as changes were made during the year as trains were dropped or added, then the corresponding page in the book had to be altered. No computer, of course, in 1929, just a lot of skilled people doing a lot of meticulous work. The union representing this part of the printing industry numbered some 90,000 individuals in 1950, and now days the union is just a memory.