Before you get to the final chapter (White Horse) where you find Raam make sure you get a torque bow and a good amount of ammo, or maybe a sniper, but I find the torque bow works better.

After the cut scene where you first encounter Raam stay where you are behind the barricade, if you move out from that cover, even if Dom leaves, RAAM will most likely shoot your face into 2389804234 pieces with the chain gun or get his Kryll to turn you into nothing but a few cuts of ham and some blood.

Sit tight and hold onto your torque bow and pop RAAM a few times in the face as he walks closer to you, I find this is the most effective if you can get perfect Active Reloads multiple times in a row, dont worry if he's in the light or not, because even if the Kryll are circling him, the explosion will push them away, and then shoot again to hurt him.

If Dom runs out and dies... honestly... who cares. You dont need him to do this. Wait until Raam gets super close to your barricade, and when he starts circling around to your side, make a break for it, and sprint all the way to the other side of the train.

There's a Troika Turret there near the light mass bomb on a platform, circle around back and walk up the ramp to jump on the turret. Now this has to be done quickly and this is why I told you to wait until he gets all the way to your side so that you have the most time to get him.

If you dont jump on and shoot the crap out of him fast, he will get in range and shoot you and get his Kryll to eat your face. Jump on the troika and blast him a while and he'll die. If you didnt hit him much with the torque, this may take longer, so make sure you screw him up good.

Hope this works well for you, works great for me every time. Just make sure when you're sprinting to the other side to try and keep cover between you and Raam, because he will try to shoot you.

Good luck, Great Gambini