Abstract: A pneumatic filter transport system has a gate (18) in a section of conveying duct (2), which gate and is openable in response to signals indicating a filter rod jam in a receiver unit (15) connected to the duct. Once opened, the gate allows remaining filters in the duct to be directed to a dump (30): this reduces the risk of a receiver jam developing into a line jam (which is more difficult to clear). The gate may be provided in a curved section of duct just upstream of the receiver. The duct may incorporate a longitudinally-extending partition (60), which allows removal from the duct of loose material (e.g., carbon granules) which has become separated from the conveyed filters. The duct may have longitudinal slots (68) which allow conveying air to exhaust from the duct upstream of the receiver.