After 300 kph the aerodynamics noise emitted by the French High Speed Train T.G.V. (Train Grande Vitesse) becomes preponderant. The pantograph and roof environment located in the top of the rear power car are one of the sources which participate in the overall noise of the train. Investigations in an anechoi'c wind tunnel are performed firstly with a real pantograph, secondly with a fine 117 scale power car model. After a trainborne Velocimetry Laser Doppler campaign, the real turbulent boundary layer is simulated in the wind tunnel. The decreasing of the radiated noise level is obtained by modifying the geometry of both the pantograph and the roof and by adding devices on the pantograph itself. These results suggest that close attention needs to be paid to the roof geometry.