A high speed train power unit comprising: carbody that comprises: a roof; a floor; a driver's cab at a front end of the carbody; and a technical compartment that comprises: a low voltage zone that comprises an air conditioning unit designed to condition the driver's cab, wherein the air conditioning unit is on the roof, a traction zone that comprises a rheostatic brake on the roof, and a technical zone, wherein the low voltage zone, the traction zone, and the technical zone of the technical compartment are respectively located next to each other along a longitudinal axis of the power unit; at least two bogies mounted under the floor of the carbody; and a main transformer located under the carbody between the bogies.