Fixed Gearbox Specification & Selection

I need a mechanical engineer who can guide me in choosing a fixed-ratio gearbox for an industrial machine now in the design phase. The gearbox will not be manual, automatic, or CVT; I specifically want a robust fixed gearbox that can meet three critical criteria: high load capacity, a defined speed range that matches our motor curve, and long-term durability in a 24/7 production environment. Your task is to analyse the duty cycle, calculate the required service factor, and translate those figures into an exact gearbox size and model recommendation. Please include: • All design calculations and assumptions • A shortlist of commercially available gearboxes that satisfy the numbers, with supplier links and lead times • A brief comparison explaining why the recommended unit outperforms close alternatives on load capacity, speed range, and durability CAD integration is not necessary at this stage; a clear technical report (PDF or Word) backed by calculations in Excel or similar will be the main deliverable.