Very high multiplicity tracking in heavy ion collisions with the NA49 time projection chambers (TPCs)

An array of four large time projection chambers is being assembled for the NA49 experiment at CERN. The aim is to track more than 80% of the several thousand hadrons produced in central 160 GeV/A Pb on Pb collisions. New concepts in TPC construction, operation and tracking-algorithms have been used to master the extreme track densities encountered in these events. First results obtained in the November 1994 Pb run will be discussed.