Catch up with the train and find the Dark One | Chapter 22: The Chase Metro: LL Guide
Last update: 11 May 2016
Get ready because, soon after you get near the train you are chasing, there will be cars with the Reds appearing to your right. There are two ways to deal with this situation. If you are OK with eliminating the enemies, start shooting at them with any machine gun or assault rifle you want, a scoped one would be best.
Still, if you are going to win an achievement or beating the game without killing anyone, you can try and survive the entire scene by crouching and healing yourself, if necessary.
Continue attacking, or avoiding your enemies (watch out for the turret mounted onto the train!), and do so until Artyom jumps over onto the train (automatically).
The assumptions of fights atop trains are similar to the ones in the beginning part of this level. If you are no stranger to killing the enemies, keep using the assault rifle or a different type of a medium-range weapon and, to the extend it is possible, aim at the enemies' heads.
If you still want to "stain your hands with blood", keep running up to the enemies close enough to knock them out. It is very important here that you make use of the covers on the way, which will allow Artyom regenerate his health or use the first-aid kits.
Stop when you reach the closed door to the car and collect the Artyom's diary page from the large crate shown in the above screenshot.
Continue on your path. Watch out for the heavily-armored soldier, especially if you are planning on eliminating all the enemies on the train. Soon after you deal with him, several long cutscenes will start and the chapter ends.