I'm new to this game and so I looked at what the trophy guide suggested to do. I began to play it on Very Hard, and found the game really quite easy. Easy that is until I get to the level where I'm on the train with the giant wheel chasing me down.

I get past the chasing boss train fine, but my problem starts after that. This point is when the helicopters arrive. There's nowhere to take cover, and I can't run fast due the weight of the minigun. Any tips on how to gun down these choppers without dying several hundred times?