double pump system

looking for possible explanations for a double pump hook-up to a dug well system. two injector pumps are hooked to the same well in pipe, this is a shallow well application. the appear to be hooked in tandem each with its own resevior tank. could pressure be a reason or maybe capacity? have never encountered such as system before,all equipment is new and of the same age and make. any information would be helpful. thanx brian

More information needed . are they side by side ,do they both come on together or alternate.does one come on alone always or does the sencond come on if needed? Are they both getting the feed from the same injector. Do they both feed the same line , Are they in parell or in line with each other.Are they on seperate circuits.

Roy Cooke sr