  Quick response times are paramount for minimizing downtime in spare parts
networks for capital goods, such as medical and manufacturing equipment. To
guarantee that the maintenance is performed in a timely fashion, strategic
management of both spare parts and service engineers is essential. While there
is a rich body of research literature devoted to spare parts management, the
problem of real-time management of service engineers has drawn relatively
little attention. Motivated by this, we consider how to dispatch service
engineers to breakdowns, and how to relocate idle engineers between base
stations. We develop an approximate dynamic programming (ADP) approach to
produce dispatching and relocation policies, and propose two new algorithms to
tune the ADP policy. We conduct extensive computational experiments to compare
the ADP policy against two benchmark policies by means of simulation. These
demonstrate that the ADP approach can generate high-quality solutions that
outperform both benchmarks across a wide range of networks and parameters. We
observe significant improvements in terms of fraction of late arrivals over the
two benchmarks, without increase in average response time.
