This achievement is story related and not missable (unless it becomes bugged, like it did for me).
*Mild spoilers*
This achievement will appear after you leave the Vavilov complex. You will open a gate, go down a path until you get to the train station. The friendly robot clerk will ask for a train ticket, which can be found at the furthest waypoint shown on screen. You will have to swim through some polymer to get upstairs to retrieve the train ticket on a dead person. Once you give the clerk a ticket to ride a train, you will be able to take a seat and the achievement will pop shortly after.
If the achievement does not pop soon after you sit down, I'd recommend reloading your game or quitting/relaunching your game. This did not pop for me the first time, so I had to replay a bit of this section.
Good luck achievement hunting this game guys, you're going to need it.
Edit:
Another method left in the comments from Schwarzio:
"what fixed it for me was reloading all the way back to the manual save point before you enter the train station. I skipped all 4 talking bodies and instead spoke to them as part of the mission rather than as if going for the necromancer achievement. Same playthrough. Hope this helps someone."