AtrackreconstructionprogramCATSbasedonacellularautomatonhasbeendevelopedforthevertexdetectorsystemoftheHERA-BexperimentatDESY,AsegmentmodelofthecellularautomationusedfortrackingcanberegardedaslocaldiscreteformoftheDenby-Petersonneuralnet.Since1999CATShasbeenusedtoreconstructdatacollectedinHERA-B.Resultsonthetrackingperformance,andaccuracyofestimatesandcomputingtimearepresented.