A turbomachine has a rotor shaft, which is mounted in a bearing
arrangement containing a hydrodynamic axial bearing, and a rotor disposed
on the rotor shaft. A hydrostatic axial bearing is additionally provided
in the immediate vicinity of the hydrodynamic axial bearing, the
hydrostatic axial bearing absorbing the axial force acting on the rotor
shaft at rest, completely or at least for the most part, relieving stress
on the hydrodynamic axial bearing during start-up processes of the rotor
shaft, and being shut off during operation at the rated speed of
rotation.