These materials came from classes that locomotive builders used to hold at their internal training departments. Customer railroads could send employees, usually Mechanical Department officials without a background as a Machinist or Electrician on diesel-electric locomotives. The ones you have were produced in the transition era and some steam men with Machinist or Electrician backgrounds might also have been sent at that time. I was sent to EMD school shortly after being promoted to Road Foreman of Engines, and thought it was a pretty good basic mechanical and electrical class. Some others had no locomotive experience at all, and the instructors paced the classes for them. I was the only former Locomotive Engineer there, and it was easier for me to understand everything. I learned how to trace a circuit, which helped me later.
Most of the locomotive operating manuals out there today are from the 1945-1965 era, as many railroads started their own internal schools beginning around 1960.
