1. Go to level select -> Modern Apartment -> Passenger Mode (Top Right with a person icon).
2. The game will spawn a group of passengers. Once you have located them, you will need to access the spawn menu (RB) and spawn in a "platform" near the group of passengers.
3. Theoretically, you are supposed to build tracks between every platform and the station. However, this is quite time consuming. Using this trick will make the process much quicker and easier.
Hold down the "view" button (The button to the left of the start button) -> Select "start point" -> This will spawn a flag. Place the flag parallel to the platform. -> Bring up the menu again, and select "reset". -> This should spawn the train right next to the platform. Wait for all the passenger to board the train.
4. Find the station. Repeat the steps to spawn the train next to the station. The passengers should exit, completing the objective and triggering the acheivement. Repeat for the other objectives in the level if you want to unlock the "Good Service On All Lines" achievement later on.
I will link a tutorial from "Maka91Productions" (Not my video, so big thanks to him for teaching me this strategy) that will show you how to complete this acheivement, as well as all the others.