  The Concurrent Track Evolution method, which was introduced in a previous
paper (DESY 97-054), has been further explored by applying it to the
propagation of track candidates into an inhomogeneous magnetic field volume
equipped with tracking detectors, as is typical for forward B spectrometers
like HERA-B or LHCb. Compared to the field-free case, the method was extended
to three-dimensional propagation, with special measures necessary to achieve
fast transport in the presence of a fast-varying magnetic field. The
performance of the method is tested on HERA-B Monte Carlo events with full
detector simulation and a realistic spectrometer geometry.
