Brakeman

Brakeman is a secret achievement in Metro Exodus that can be obtained in the level  Moscow.

Overview
This achievement can be unlocked towards the end of the Moscow level when the player is tasked with destroying the train that is pursuing the Aurora. As the player transitions between the train cars, before entering the door that takes them to the next car, a switch can be activated that will release the car the player came from. There are only two that need to be released and this must be done before entering the door to the next car. Look down and to the left of the door to see a prompt to release the car. The achievement will unlock after releasing the second car.