The conveyor installation makes it possible to control the speed of items of the bottle (1) type dispatched in several trains distributed across various paths in the form of single-file lanes (11). The lanes are delimited by a pair of walls (16, 17) which are arranged in an omega shape over a base plate made up of several juxtaposed conveyors (13, 14, 15). Each lane (11) may comprise a fixed wall (16) acting as a reference, and a moving wall (17) that can be adjusted according to the dimensions of the items that are to be conveyed.