Dominic Mazoch posted:If one can find an old SP employee timetable of the 1970's, look in the back. There were serveral formulas about where to place helpers. At that time the electronic controls for the remotes were not as robust as today's. Plus there were no AC traction motors on diesels.
History of another period.
My guess there are like formulas for today if DPU units are placed on a train.
I would guess that computers and algorithms might be used now to calculate the most efficient placement of engines for each individual train, based on a number of variables, such as load tonnage, distribution of load tonnage, power of the individual diesels to be used, route travelled including factors such as grades encountered enroute, speed requirements and achievement of optimum fuel economy.
