Abstract: A zero pressure accumulating conveyor is provided from a standard belt driven live roller section and "bolt-on" accumulating elements. The accumulator includes a plurality of accumulation zones, each zone having an article sensing apparatus and frictional braking apparatus for braking at least one roller, and preferably less than all rollers, in the zone. Each sensing apparatus includes a first valve, actuated in response to an article in the respective zone for pressurizing the brake apparatus. All zones, except the downstream-most zone, have second valves. The second valves, in a respective zone, are opened in response to actuation of the first valve, in the immediate downstream zone, for passing the pressurized air from the first valve in the respective zone to the brake apparatus in the respective zone only when an article is sensed in the immediate downstream zone, and a subsequent article is sensed in the respective zone.