This is an in-feed line for a flexo folder gluer equipped with pre-feeder. Because the converting machines are not aligned, the stacks are stored on a dedicated buffer upstream the machine, and a secondary shuttle car is moving the stack from the buffer to the in feed line. In this case the system is operating in semi-automatic way, so it is the operator that by a console, selects the line from where the shuttle car is taking the board. Once the stacks are on the in-feed line, the system operates to have full accumulation, and to separate the piles just upstream the pre-feeder.