  By using a correlated projection operator, the time-convolutionless (TCL)
method to derive a quantum master equation can be utilized to investigate the
transport behavior of quantum systems as well. Here, we analyze a
three-dimensional anisotropic quantum model system according to this technique.
The system consists of Heisenberg coupled two-level systems in one direction
and weak random interactions in all other ones. Depending on the partition
chosen, we obtain ballistic behavior along the chains and normal transport in
the perpendicular direction. These results are perfectly confirmed by the
numerical solution of the full time-dependent Schr\"odinger equation.
