This paper describes the design concept and construction of a continuous operating cold flow transonic test turbine facility, which is a unique combination of a 2 MW axial test turbine and a direct coupled brake compressor. To cover the losses additional air is provided through a separate electrically driven compressor station and fed into the turbine inlet casing via special mixer inserts which are also fed by the hot compressed air from the brake compressor. The main test rig dimensions and its capabilities are outlined. A brief description of the design process with step by step advanced technology design methods is presented from the first ideas up to the latest plant expansion for special testing conditions where two industrial transonic turbine stages will be tested. The aerodynamic and structural design of our transonic single turbine stage (TTM-Stage) is described in detail and the results of the respective flow simulations are presented.