Cifrele de 80 km/h si 190 km/h sunt reale // Calcule bazate pe filmul video care a aparut pe internet, harta Google Maps a caii ferate si cartea tehnica a trenului care a deraiat. CONFIRMED! The max. speed allowed in that curve was indeed close to 80 km/h. Also the train speed was about 190 km/h. The lateral centrifugal force that derailed the train was 4.5 times greater than the maximum the train could have sustained. Explanation: Using Google maps the curvature ray (R), of the track where the train derailed near Santiago de Compostella, can be derived by measuring the length of the bend between two points (L), the straight distance between same two points (d) and the formula, R*sin(L/2R)=d/2. I made the measurements and found R = 512 m. (there could be an imprecision of +/-25 meters). The lateral acceleration of the train (a) in the ray direction can be calculated using the formula a=v^2/R, where v=the train speed. Doing the calculations I found that: 1) v=80 km/h -> a=0.96 m/s2 (below max. 1.2 m/s2 supported by Talgo 250 trains) 2) v=190 km/h -> a=5.4 m/s2 (much beyond what a Talgo 250 can sustain) Regarding the train speed: - The Talgo 250 train that derailed was 183 meters long. - 3.4 seconds passes from the moment the locomotives appears in the video till the end of the train is visible. Estimated speed = 183 m / 3.4 sec = 193 km/h (close to 190 km announced by newspapers) In conclusion, The Talgo 250 train entered the curve with a speed far beyond the derailment limit. Something terrible wrong happened. The brakes malfunctioned either themselves or the automatic breaking system, that overrides the train driver inputs, did not work properly.