In this mod, locomotives are simple chassis that have to be outfitted with equipment. With new technologies, you will develop better equipment to make your trains faster, more powerful, and able to navigate without a driver. Trains start out weaker than the regular Factorio locomotive, and several tiers of research increase their power.

Modular Trains can be played with or without Space Age. When it is played with Space Age, it requires an additional mod for Space Age graphics. The first tier of train technology is acquired on Nauvis, and each planet has a new train technology. Without Space Age, all features are available on the starting planet.

I made this mod to demonstrate a train upgrade system that uses equipment instead of new locomotive items. There are two new equipment types, namely engines and controllers. Engines make trains go. Controllers tell them where to go when nobody is driving.

Some graphics are placeholders.

Known issues

Replacing equipment in a locomotive that is directly underneath an elevated rail may move it to the elevated rail.
The train GUI closes when a train is reconfigured.