The Change Ledger exists for one simple reason: rebuilding is hard work.

When optimising a factory, it is not enough to simply present the final, perfect layout. The process of getting there takes time and effort. If you want to play Factorio realistically, that effort matters.

I have already developed an accounting system for materials. I created Big Brother to monitor player activity. However, something was missing: tracking how the factory itself is rebuilt.

Some people just wipe everything and rebuild from scratch. Clean. Simple. But also expensive. Smarter players rebuild step by step. They move machines. Rotate things. Replace parts. They improve sections without tearing the whole place down. The Change Ledger records these changes.

It logs structural changes. It also logs what got removed. What was placed where. What was moved. This includes players and robots. I also integrated things like picker dollies because it is cheaper to move a machine than to demolish and replace it. That difference should matter.

Currently, it only tracks the structural side. What’s still missing is the accounting connection. If you remove a chest full of items, they don't just disappear. It has to go somewhere. That part will come next. The Change Ledger will send the accounting system the correct messages so that material movements during rebuilds are recorded properly.

The goal is simple: You start with an operational factory. Your job is to improve it. You have 100 in-game days to do this. Maximise output, but do so with controlled effort. Brute-force solutions shouldn't automatically win. Demolishing everything and constructing a large main bus shouldn't be the cheapest option. Optimisation should be balanced against rebuild cost.

Achieving that balance is the whole point.

This is the idea behind the Change Ledger.

Factory Ledger → Material & Inventory https://mods.factorio.com/mod/logistics_simulation
Big Brother → Activity & Behavioral Monitoring https://mods.factorio.com/mod/big_brother_1984
Change Ledger → Structural Governance / Engineering Change

Transparency Notice

Yes, I relied heavily on AI tools while building this. I used ChatGPT (including my own customised writing assistants), Claude and Gemini. The images were generated using the ChatGPT image tool. Not because I’m lazy. It's because I want working systems quickly.
I’m a logistics professor. I care about whether the system works, is consistent and can be operated cleanly. That’s it. Tools are tools. If they speed things up and improve the outcome, I use them.

Development Effort

Just to be clear: this wasn’t built in a weekend. As of mid-February, there are roughly 150 hours in this project.
That includes coding, testing, documentation, balancing logic, and the case study work around it.
AI helped speed things up. It did not replace the thinking. Designing a consistent system, connecting accounting, player behavior, structural changes — that still takes time. So no, this isn’t something thrown together in an evening.