I'm working on the academic design of a gearbox for an escalator application (operating ~18 hours/day, moderate shock conditions). I'm referencing AGMA 2001-D04 for gear design and ASME A17.1 for escalator safety requirements.

However, I noticed that while AGMA 2001-D04 defines the safety factors for pitting resistance (S_H) and bending strength (S_F), it does not provide recommended values. Similarly, ASME A17.1 gives static safety requirements for escalator shafts but does not address fatigue safety factors.

My questions:

I'm looking for values or references that can be reasonably cited in an academic context (textbooks, standards, or gear manufacturer design guides).

Thanks in advance for your help!