no bus, 0 truck, only trains
I tried to test if it's possible to have enough throughput only using trains and use no belt system.
The system and learnings:
Overview
- There are 36 trains supporting ~6k pop (have like 7 idle trains on avg so can be done with ~30 trains)
- 0 notifications, all items delivered.
- The trains have 3 T2 modules. More than this is too much space, less than this doesn't have enough throughput.
- I skipped a few types of deliveries (1) raw material. It's a different network. This experiment tests to replace the bus (2) food, since it should have a dedicated train rather than a single network otherwise each food type will have 1 train meaning 11 different trains just to support food. Better to separate it to a different dedicated line (3) didn't have space station. The system would still support it (4) sinks for co2/rock/slag etc. are set to "empty" in sandbox. Real world use case would generate a few more resources that needs to be transported. The system would still support it.
Learnings
- Traffic cannot stop. Need around ~3 trains length of space in front of all stations. Limiting to 3 helps. If it's 2, then not enough trains are on the way (depends on distance) and causes issues
- Waiting station. When bigger consumptions like construction parts are idle, a lot of trains go idle. Need a big waiting station. I thought the waiting station throughput would be a blocker, but it wasn't. Trains were able to leave relatively fast.
- Many mixed stations. Check Image 3/4. I did a checker pattern with stations. This allowed trains to have enough gap between each other. Since all trains were loading/unloading same speed, this pattern allowed to increase throughput by ~9x compared to single station.
- 2 loader/unloaders per station. High throughput items like steel, copper definitely needs 2. Can be more but not needed. Even low throughput resources like gold requires 2 loaders/unloaders is recommended. Main reason is if loaders/unloaders have different throughput, it effects other trains throughput thus effecting the whole system
- v4 Storages everywhere. Check image 5. The mixed stations in a network only allows one type of item being delivered to a station. It decides how much to load by checking how much space there is to fill. So if you have small storages like ~400 items, the train is mostly empty. By the time it goes there, the box gets emptied and you are struggling. The solution is to have big storages. I had to put multiple big boxes of CO2, Waste, Slag, Recyclables so there are enough trains on the way that sustains consistent throughput. Everything else single v4 storages are sufficient. I used a few places v2 storages. I wouldn't do again. Everything (regardless of how low throughput requirement it has), I'd use v4 storages.
Minor stuff
- I used an ellipses route for trains. it was alright. There were a few weird places where I had to add lane swaps so train could go other direction
- Trains still use a lot of space.
- 2 headed trains uses less space, but it doesn't work mainly because argument #1, trains cannot stop. High throughput resources typically have 2-4 trains in-transit always. 2 headed means, there is not waiting stations. if there is, it defeats the main benefit of using less space.
- The other images are showcasing (a) single network with all stations (b) waiting stations and fueling stations (c) low maintenence cost. I thought the maintenence cost would be much lower without a bus but it's still high. My real game with bus has ~1250 maintenence I for conveyers. Without the bus, same blueprints, it's around 600 maintenence I.
- I capped at 6k pop. If it was 12k, the system would struggle. There would need to be 4-8 trains in transit to sustain the throughput. Everywhere would need to have 2x v4 storages, longer trains, more space for incoming trains etc. The whole layout would need to change.
--
tl;dr - It's possible to not have main bus, and deliver all items by trains using a single network with the new update.