Defending the train against enemy attacks | Mission 6:
From Hell's Heart Crysis Warhead Guide

Last update: 11 May 2016

You won't need a map of the area for this assignment, because the entire battle will take place around the container. Obviously you shouldn't wait for the monsters to show up. Instead, use the free time to find a large ammo stash (screen). I would recommend that you choose a good second weapon. You can take a Gauss rifle (better choice) or a minigun.

This battle can be played out differently, depending on the difficulty level. If you think you're skilled enough, you may consider going back to the cannon in order to use it to kill alien creatures (screen). You could also use two miniguns. Sadly, this won't be possible on higher difficulty levels, because you would lose too much health before inflicting any serious wounds to the monsters.

Sooner or later you'll probably going to have to jump off the train to deal with the alien creatures yourself (screen). Focus mostly on killing flying monsters, because they can attack you with their powerful freeze ray. It's also important to return to the ammo stash between waves in order to acquire necessary supplies.

Obviously you will have to avoid sustaining major injuries, especially while being attacked by larger creatures (screen). Notice that this objective may be completed even before you'll deal with all the monsters. As a result, you will have to get rid of the rest quickly and get back on board the train before it leaves this area.