A device for assembling and disassembling a component of a gas turbine, having a rail system with at least two running rails. A carriage which can be pushed on the running rails along a specified movement axis is provided on the running rails, and the carriage has a securing device which is designed to secure a fitting section of a first carriage insert in a force-fitting manner such that the first carriage insert is moved together with the carriage when the carriage is moved on the running rails.