Uncharted 2 Remastered - Defeating Train Boss (Crushing difficulty)

To defeat the Train Boss keep shooting/fighting him and throw grenades (if you have them) and when his 'helmet' eventually 'pops off' is when you have the chance to defeat him. Once his helmet has fallen off you can then lay into him with a final fist-fight which eventually knocks him out.... When his helmet falls off keep pressing the Square button to fight him as you would normally then near to the top of the train boss's swings, when his arm slows down slightly, time a hit to the Triangle button to dodge his punches, then continue hitting the square button until he goes to hit you again, after about the third time of successfully dodging his punches you then just keep hitting the square button to completely knock him out... Sometimes the triangle and square symbols don't appear, if they don't, you've just got to visualize them and judge your timing right. In fact you don't need the prompts to show at all, it's just simply dodge his punches with Triangle and punch him with the Square... Good luck.