The invention relates to a device for installing and removing a component on a gas turbine, having a rail system on which in particular a rotor can be displaced along a predetermined displacement axis, and having a terminal positioning part which is fixedly connected to the rail system. The positioning part has at least one guide portion which is designed to co-operate mechanically with a respective counterpart guide portion on the housing of the gas turbine, in order to achieve a suitable orientation of the device with respect to the housing of the gas turbine. The positioning part also has at least one connecting section which is designed in each case to form a fixed but releasable connection to a respective counterpart connecting section on the housing of the gas turbine construct.