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Tutorial:Transport use cases

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This page compares the three main Transport methods: Belt transport system (conveyor belts), Railway (trains) and Logistic robots. Note, that there are two more useful methods to transport stuff: The characters Inventory and the Vehicles/Car. (Especially the car has an extremely high capacity and can be used instead of trains - of course you need to drive everything yourself, see the chapter about the car).

The best choice depends on the context in which they are used. For example on the amount of resources you need to transport, or how far away they are.

Comparison of Belts, Trains and Logistic Robots

Belts Trains Logistic Robots
Throughput Constant, slow, precisely calculable, limited Extremely high, fast, not easily calculable but constant, nearly unlimited if enough space, High in small areas, not calculable/chaotic, unlimited if enough bots, cannot be optimized, terrible over long distances and bulk goods
Space required Small for simple products, large for complicated product chains Large due to train stations and bends Small for complex products
Optimization Highly optimizable. Source of never ending fun. Seldom really needed - better rebuild or built more tracks. For larger networks you can get some trouble with deadlocks/gridlocks, if not optimizing. Optimize train stations: connect either with belts (complex) or with logistic bots (recommended). Optimize placing of roboports (for charging) and used number of ports vs. number of bots in the air.
Initial costs Very small as long as conveyor belts are short. Still good with parallel belts. Larger when making express transport belts. Expensive with express; should be used for special cases only. Considerable amount of material is needed for initial locomotive. Small costs for making rails. Roboports and especially bots require a lot of resources to make.
Use of energy Gratis. Free. Always an object of discussion. ;) Low. The usage of fuel is currently very affordable. High. The roboports need a lot of energy and the bots take even more energy, as more are in the air. This can be a big problem, but is normally not an issue.
Maintenance costs None Some fuel needed Considerable amount of electricity needed
Pollution None Some None, indirectly caused by use of electricity.
Best used for High throughput, small to medium distance. Examples include raw materials and simple products. High throughput, long distance. Examples include transporting ores or plates from resource fields to main factory area. Extremely high throughput over very short distances (< 50 tiles), low to medium throughput over medium distance (50-500), catastrophic over long distance. Best used in main factory area for complex products like modules and advanced circuits. Also best used for products needed in smaller quantities like placeable structures and ammunition. Unbeatable for train station (loading/unloading chests).
Most annoying problems Need to optimize curves (is on the TODO-list), blocking (also), left/right lane problems (part of the game), splitting off the right amount of items (also). Deadlock situations (in complicated crossings), complicated to lay long rails, built up of train stations. Blocking of roboports by waiting for charging, "stupid" behavior that far away bots are used, instead of near.

Experts

Belts

  • practical up to distances of 500 tiles (to compare: a radar station watches up to 200 tiles (100 tiles "radius")).
  • connect small resource-fields to the factory area, as the capacity of a belt is limited to about 700 items per minute in the best case, when using basic belts. With fast or express belt, this is higher (up to 1750) but the price is gigantic. Using multiple parallel belts is costly, but with basic belts still affordable over long distances.
  • Conveyor belts are best for working within an automated facility for bulk goods. transporting ore, plates, circuit boards, etc over short or medium distances.
  • they store over a long distance a not to be underestimated number of items (about 12 per tile, with two lanes, so you can calculate over 500 tiles with 6000 items!). This storage is out of reach and could be counted as wasted, until it is transported.

Note: the length of 500 tiles is just a "rule of thumb", and comes from these facts:

  • It takes nearly 5 minutes (4.44) for an item to run from one end to the other (Basic belt).
  • A belt with 500 tiles stores about 3571 items (about a chest of resources).
  • The fact, that about after this length it makes sense to use train.

The advantages of belts are:

  • coming to transport-performance, belts deliver very constantly
  • easy calculations possible (e. g. is belt able to transport output of all mines)
  • basic belts are cheap compared to tracks and it is built faster
  • you see how much items are on the belt
  • the belt works like a small storage: you can store 71 items in a length of 10 belts, when using both lanes (but for long belts this is a big disadvantage!)

Disadvantages:

  • already said: limited transport capacity, cause limited throughput.
  • slow. This is a problem with verily long belts because it takes a while to fill the belt. The items on the belt cannot be used. A belt with length of 100 holds 714 items for 56 seconds. With trains this is much lower (10 seconds) and as long as they are not loaded into a wagon, they still can be used.
  • Belts work normally fine up to 80% of maximum capacity. Belts are not thought for using with full capacity. As described in belt physics above, the tighter you compress the items, the more inefficient it can become.

Belts have the best short-distance throughput for continuous, direct-to-factory transportation. This is especially true, if you use basic belts in parallel, cause this combination has an incredible high throughput at low costs.

Trains

  • Trains should be used to get items from big and distant resource fields. Nothing can compare with it, especially, when thinking about speed. The planning is difficult and the building itself is currently tedious. (tip: use the train to build the rails, this is much faster: sit in the train and build the next rail before you, hold mouse, start driving slowly. You can use it also to build the power poles like so).
  • Trains are for linking separate factory assemblies together over long distances. This additionally lets you 'take a ride' out to outposts that require attention.

Smelt ore locally and ship the plates via train, you can double your wagon capacity and route directly to a storage yard or factory. See also Transport/Compress_by_Pre-production.

Some interesting thread: Long distance transport.

Logistic robots

  • Bots are terrible at long distances and bulk goods.
  • Logistic robots should be used in a limited area with dense building placement In most cases this is the main factory area. With some updates the logistic bots can handle enormous amounts of items.
  • Bots can help make links for end products of one chain move to where they're needed within the local network, especially if it's completely impractical to route a belt for the job.

Bots, while great at moving sparse items with slow production speeds, are a very costly thing to integrate with high-volume affairs like mining/smelting because they need frequent breaks to recharge.

The exception is the incredible benefit they offer to train stations because of the space/logistical challenge of routing and load-balancing belts around the train tracks, especially since it isn't necessarily 'constant flow', offering them time to recharge.

Seeing from throughput side

A Basic transport belt cannot transport much more than 700 item/minute and an Express transport belt (the fastest) not more than 1750 (see above). Now compare that with a locomotive: a Cargo wagon can deliver 1500 items (ores) per wagon! And if you smelt the resources at your outpost and transport intermediate plates (copper, iron) you can transport 3000 per wagon. So when speaking from throughput, you need to swap to train or make multiple parallel belts.

This picture might change when you developed Logistic robots. But that is not true! They can't be beaten for relatively small areas, especially with their researched bonuses, and they have some kind of intelligence; they try to deliver all requests as equally as possible.

But bots are terrible at long distances and bulk goods. Here are some calculations, which explain the problem (all calculations are assumed with full upgrade for the logistic bots!):

Needed robots to transport 3000 items per minute over a distance of 50 tiles you need: 

Robot speed:                     3 tiles/sec (basic speed) * 1.4 (logistic speed bonus) = 4.2 tiles/sec
Needed time for one transport:   100 tiles / 4.2 tiles/sec = 24 secs
Need robots per minute:          24 secs / 60 secs = you need 0.4 bots to transport one item per minute over 50 tiles.
Because of Logistic robot cargo: 0.4 bots / 5 items per transport = 0.08 bots to transport one item per minute
Total:                           3000 items * 0.08 bots/per item = 240 bots

240 is a high, but still very realistic number for a logistic network with 4-5 roboports.

Needed robots to transport 3000 items per minute over a distance of 500 tiles you need: 

Needed time for one transport:   1000 tiles / 4.2 tiles/sec = 240 secs
Need robots per minute:          240 secs / 60 secs = you need 4 bots to transport one item per minute over 500 tiles.
Because of Logistic robot cargo: 4 bots / 5 items per transport = 0.8 bots to transport one item per minute
Total:                           3000 items * 0.8 bots/per item = 2400 bots

2400 bots need a quite big amount of resources to produce, not accounted the needed research (for bots, speed/stacksize bonuses), number of roboports and the needed energy.


That leaves conveyors and trains.

Trains are faster than belts and offer better logistic control as you go between logistic networks.

Belts simply take forever, and you may wind up with a lot of asset tied up with simply being 'in transit'. You should see items sitting on a belt as "non-useable storage". Backed up belts can be a good thing for buffer space, but long belts are just inefficient, or better: You loose the control over the other end, due to the long gap; the resources on the other side could be long depleted, but you see it only five minutes later.

Or in other words

The afford, to squeeze out the last 20% of belt-performance rises depending on distance and total amount and at some point the train will win. But in your central factory area the bots will never be beaten. On the other hand: in small areas, and for simple throughput of one type of item (furnace iron ore to iron-plates for example) we can place some belts in parallel, which is cheap and efficient (uses no energy) and when using parallel belts we reach also enormous throughput. For later game, the Fast transport belt is a good compromise between cost and efficiency, and the Express transport belts should be use only for short sections like curves or some special cases.

Or in more other words

The amount of robots you need is directly dependent on the density you built. The central part of your factory should be dense, cause not only throughput is important here, but also speed: How fast can an item be produced in total (including the transportation time).

See also

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