is as follows 1 the servo controlled feeder belt 20 advances the shingled mailstream forward at full speed or approximately 130 inches per second 2 when the lead piece of the shingled mailstream reaches the accelerator belt as determined by the photocell array 36 and 38 the feeder belt 20 reduces to 40 of full speed or approximately 52 inches per second the time at which the lead edge of the mail pieces reaches accelerator belts 40 and 42 is recorded for future use 3 the lead mail piece is grabbed by the full speed accelerator belts 40 and 42 and is separated from the remainder of the shingled stream at a rate determined by the difference in speed of the accelerator belt and the feeder belt this is 60 of full speed or approximately 78 inches per second 4 when a gap is detected by the photocell array 36 and 38 between the lead mail piece and the remainder of the shingled mailstream the feeder belt and thus the shingled mailstream is stopped 5 the shingled mailstream is stopped for a period of time governed by the following equation time desired pitch 130 travel time at full speed to last photocell in array present time time at step.