Railway Empire 2

The way co-op works in this game is that up to four people can play on the same map together (one host who owns the save file, and three guests). Guests can be brought in as teammates or spectators. Teammates have access to your network, resources and money, so they are basically an extension of yourself (for example, you can build one section of your network while they focus on another).

The good news is that any game can be turned into a co-op game at anytime and this achievement only takes a couple minutes if you have a partner. Simply start a new game or load any game you already have and do the following:

• On Xbox, hit start and in the pause menu, scroll down to multiplayer and click that
• On PC, it's at the top middle of the screen and consists of an image of two monitors

In the multiplayer menu, scroll down to "New Player" and change that to "Open". Now either press the "Invite Friends" button at the bottom if they are on your friends list, or send them the code at the top of the page. If you are joining a game with a code, then you will need to select the "Multiplayer" option in the main menu of the game to input the code there.

It does take a bit for the guest to join as it has to download your entire rail network, but once they join, the achievement pops for all players in the game.

Solo Method

If you have two Xboxes, or an Xbox and a PC, this is very easy to do by yourself. Have a dummy account launch Railway Empire 2 on your primary (your home Xbox). You want to do this because your home Xbox shares Game Pass with anyone who plays on that Xbox, so you do not need a gold account or Game Pass for your dummy. Then just have your main play on your second Xbox or PC (assuming you bought Ultimate). I just put my laptop next to me and played on that while my dummy was logged in on my Xbox. Super easy.

Note that you can't unlock achievements in sandbox mode.

Let me know if you have any questions.