The first step is to locate a locomotive. Where they spawn depends on your server's setup. On your way to find it, you should look out for the following items:

• Truck battery (required)
  
• Locomotive engine belt (required)
  
• Glow plug (required)
  
• A car radiator - Needed to prevent the locomotive from overheating quickly
  
• H7 headlight blub - Needed for the far light beam of the locomotive
  
• Electric control unit - Allows to operate rail direction switches remotely
  
• Compressed air hoses - Train can only slow down but not STOP without these. The handbrake must be used instead then.
  
• Cabin glass panes - Both big and small to fix the locomotive windows. A full set can sometimes be found in a replacement box for them.
  
• Wrench - Used to sabotage and repair the direction switches on the rail tracks. Also used to empty a liquid wagon.
  
• Lockpick - Allows you to lock/unlock the boxed wagon doors. Will also work on the locomotive in future updates.

Here is a visual overview of the interactions on the locomotive: https://i.imgur.com/Mc5RIFj.jpeg
Besides the required attachments the most important resource is fuel. The locomotives use diesel - not gasoline like cars. So you have to use a liquid container such as bottles and jerrycans and siphon off diesel from the WHITE industrial tanks. Careful jerrycans sometimes spawn with gasoline by default so empty them first!.
The locomotive can be refueled on the fuel tank caps. It can hold up to 20 jerrycans worth of fuel which will last for 30 real time minutes of driving at maximum engine power. If you want to carry more fuel with you try and find a liquid storage wagon. On those, any liquid can be filled in from the top and drained from the sides. They can hold a total of 20 jerrycans worth of liquids.

Before you start driving you should check that the handbrakes are disengaged on your locomotive and all wagons that might be pre-attached to it or else you will struggle to move. In the locomotive, there is a turn handle to interact within the cabin, on wagons it is externally on the sides.
The train can be controlled in two ways. By default, the simple mode is bound to WASD. The buttons must not be held.

• W = Drive / accelerate in the direction the driver is facing
  
• S = Slow down and reverse eventually to go backward
  
• A = Instruct the nearest lane switch in your driving direction to go left
  
• D = Same as above, but to the right

If you are used to playing train simulators and controlling a locomotive with a reverser, throttle, and locomotive-brake lever then you can go into the keybinds menu and assign those.
Besides these keys, you can also use the vanilla game key binds for (H)orn and (L)ight as a train driver. Holding L allows you to turn off the light directly instead of cycling through them. Additionally the (C)rouch button allows you to duck into cover to make shooting you harder. This will restrict your camera for fair gameplay.

You can switch diver positions while in first person and the throttle is in neutral, by looking at the other dashboards direction.

Now that you successfully drove around with your locomotive you might want to add some wagons so you can transport more things. If you find any you can drive up to them slowly and interact with the chains on both ends to couple them together.

The wagons do not have a virtual inventory like cars. Instead, you either drop the items onto the floor or organize them into barrels and other containers that you put down on the wagons. Similarly, base-building-related items such as generators and spotlights can be built on top of the (moving) train to give it more utility. Full base building with walls etc is currently not actively supported, but I will look into it as part of the roadmap.

If everything went well you now have your own little mobile base you can take on loot tours around the map with you. Just make sure to stay within range of fuel sources to stockpile enough so you do not get stranded.
If you found any bugs or feel like something is unfun/unbalanced, please join my discord and report them, or make a discussion topic here on the workshop page. This helps me improve the mod, thank you.