Official Factorio Wiki - User contributions [en]

Deconstruction planner

2018-05-11T18:10:44Z

Kmkkmk: Artifacts have been removed.

{{Languages}}
{{:Infobox:Deconstruction planner}}

Deconstruction planner is an item which allows the player to mark entities for removal. Marked entities will be removed by [[construction robot]]s in construction network range and stored in [[storage chest]]s.

You can use the deconstruction planner to '''cancel deconstruction''' <sup><i>(since v0.11)</i></sup>. First, click the deconstruction planner to pick it up. Then, shift+click and highlight the area marked for deconstruction to cancel it. The deconstruction planner can also be used to order [[construction robot|robots]] to pick up items off the ground.

== Achievements ==
{{Achievement|automated-cleanup}}

== History ==

{{history|0.15.0|
* Blueprint library: Allows for keeping players blueprints between individual game saves and allows sharing blueprints in multiplayer games.
* Added ability to export and import blueprints, blueprint books, and deconstruction planners as strings.
* Blueprints, blueprint books and deconstruction planners are obtainable from the library GUI with no crafting cost.
}}

{{history|0.13.0|
* Several non-stackable items can be swapped directly with counterparts, this includes the deconstruction planner.}}

{{history|0.11.15|
* When using the deconstruction planner, the [[logistic network]] is not drawn if the mouse is over a GUI element.}}

{{history|0.11.0|
* Added a cancel deconstruction option to the deconstruction planner.}}

{{history|0.9.0 (?)|
* Introduced}}

== See also ==
* [[Blueprint]]
* [[Roboport]]
* [[Construction robot]]

{{ProductionNav}}
{{C|Tools}}

Robotic network

2018-05-11T18:07:46Z

Kmkkmk: changed in 0.16.0: "Roboports now provide the repair packs they have for other robots to use."

{{Languages}}

The '''robotic network''' was introduced with v0.8.0, which also added [[Repair pack]]s and [[Construction robot]]s. [[Roboport]]s are the base of the robotic network. [[Robots]] can fly inside this network to every point covered by the roboports. Roboports are expensive both to craft, and to power.

==Items==

{| class="wikitable"
!colspan="2"|After researching {{icontech|Logistic robotics (research)}} [[Logistic robotics (research)|Logistic robotics]]:
|-
| {{Imagelink|Logistic robot}} || Moves items between robotic network storage chests, or to/from the player with proper research.
|-
!colspan="2"|After researching {{icontech|Construction robotics (research)}} [[Construction robotics (research)|Construction robotics]]:
|-
| {{Imagelink|Construction robot}} || Repairs broken or replaces destroyed entities. Builds, replaces, and removes entities on command.
|-
!colspan="2"|After researching {{icontech|Logistic robotics (research)}} [[Logistic robotics (research)|Logistic robotics]] or {{icontech|Construction robotics (research)}} [[Construction robotics (research)|Construction robotics]]:
|-
| {{imagelink|Roboport}} || Spawns the robotic network. Holds and recharges robots and provides the coverage for logistics and construction
|-
| {{Imagelink|Storage chest}} || Makes items available in the robotic network. Provides storage to the items collected by the robotic network.
|-
| {{Imagelink|Passive provider chest}} || Makes items available in the robotic network. Unlike the Storage Chest, doesn't accept random items from the robotic network.
|-
!colspan="2"|After researching {{icontech|Logistic system (research)}} [[Logistic system (research)|Logistic system]]:
|-
| {{Imagelink|Requester chest}} || Can be configured to request items from the robotic network storage. Like the Passive Provider Chest, doesn't accept random items from the robotic network.
|-
| {{Imagelink|Active provider chest}} || Available logistic robots remove items from this chest as soon as possible.
|-
| {{Imagelink|Buffer chest}} || Functions as both a [[requester chest]] and [[passive provider chest]].
|}

==Robots==

Robots perform any required functions within their coverage area. They need power to keep flying at normal speed. When they have nothing to do, they fly to the nearest roboport to sleep and recharge. There are two types of robots that interface with the robotic network, [[Construction robot]]s, and [[Logistic robot]]s.

== Damage Repair ==

All broken entities will be repaired with [[Repair pack]]s by the [[Construction robot]]s. Destroyed entities will be replaced, if they are available in the same logistic network.

==Number of bots in a robotic network==
The number of robots per network is soft-limited because roboports have limited space to charge flying robots. So the number of bots in a network depends on:
* the number of roboports
* the average distance between the roboports (density)
* the form of the robotic network/placement of the ports
* average distance the logistic bots fly between Logistic Chests
* how much damage the [[Construction robot]]s must repair and how often they need to place or remove buildings
And in general:
* number of bots flying
* number of bots stored in roboports
As a rule of thumb between 50-100 bots per [[Roboport]] is possible.

==Optimizing a robotic network==
The transportation-power of the logistic bots is nearly constant! It depends on
* [[Worker robot speed (research)|Speed of the bots]]
* [[Worker robot cargo size (research)|Cargo-stacksize]] (number of items they can take at once)
* Number of bots
* Average distance between your chests (all combinations)
* How often they fly empty (the more "random" the transport is the better, because then there is a bigger chance that an empty robot is near!)
* How long they need to wait for recharge - this effect is "blocking", which means that up to an unknown maximum, the transport-power is constant. But, if the waiting queue gets too long, the system falls apart, which means that, counter-intuitively, a slightly lower number of bots is actually more efficient/faster!

To optimize it, one can
* Research speed or cargo-stacksize.
* Add more bots to your network
* Add more roboports at strategic points
: This is an expensive enhancement and sometimes doesn't help, but can solve the problem
* Decrease the average distance between the logistic chests
* avoid transporting a lot of raw material - instead use transport belts for items with a lot of throughput. Bring the big material flows as near to the target as possible. The transport-power of logistic bots is much bigger than belts, but a constant flow reduces their effectiveness by about half, because they fly empty about half the time.
* Split a big network in two and move items between them with transport belts or trains (and requester/provider-chests).

===Example===
It's a very good idea to use a robotic network at a train station to unload the chests that have been filled by the inserters from the wagons. The logistic bots have enough time to recharge between trains. But don't also use them to transport the ore to the furnaces. For that the belts are much more useful, because the furnaces have a constant need for raw material and for constant flow belts are much more useful. This shows the flow:
Wagon ---Inserter---> Provider chest ---Logistic bot---> Storage- or Requester-chest
Requester-Chest ---Inserter---> Belt ---> to the furnaces

==Choosing the post for charging==
Normally a robot flies to the nearest roboport to recharge. If the queue on that roboport is too long, they eventually choose another port. This is specified by the ratio of <distance to different roboport in tiles> / <queue size of robots waiting>.

Currently, to choose the more distant roboport, the distance must be at most <Number of robots in the queue and on the way> / 2.

So, to choose a roboport that is 10 tiles more distant, it has to have 20 less robots waiting in the queue.

== See also ==
* [[Robots]]
* [[Logistic network]]

Bulk inserter

2017-03-30T20:27:24Z

Kmkkmk: 3 stack inserters are (almost) enough to saturate an express belt.

{{:Stack inserter/infobox}}

The '''Stack inserter''' is an electric inserter that can move more items at the same time. It was introduced in game version 0.13, replacing the [[Smart inserter]] that had been made unnecessary by changes to circuit and logistics functionality.

Moving at the speed of the [[Fast inserter]], it transfers multiple items per cycle to give it a material flow advantage at the cost of additional power consumption. When transferring between chests or [[cargo wagon]]s it picks up and drops off the entire stack of items instantly. When picking up from or dropping off items onto a [[Transport belt]] a stack inserter needs to grab or drop each item individually, increasing the time between arm swings and lowering its potential throughput. In these cases, however, the stack inserter still has higher throughput than a [[fast inserter]] because it swings back and forth less often. A fully upgrade stack inserter will move up to [https://forums.factorio.com/viewtopic.php?p=189599#p189599 766 items per minute]. With the maximal throughput of an express belt at [[Transport_belts/Physics|2400 items/min]] this means that three inserters will (almost) saturate a single express belt.

== Stack size ==

The stack size is increased by the [[Inserter item stack size bonus]] technology.

{| class="wikitable"
! Inserter capacity bonus
! Stack size bonus
! Total stack size
|- align="center"
| align="left"| none || 0 || 2
|- align="center"
| align="left"| 1 || +1 || 3
|- align="center"
| align="left"| 2 || +1 || 4
|- align="center"
| align="left"| 3 || +1 || 5
|- align="center"
| align="left"| 4 || +1 || 6
|- align="center"
| align="left"| 5 || +2 || 8
|- align="center"
| align="left"| 6 || +2 || 10
|- align="center"
| align="left"| 7 || +2 || 12
|-
|}

== History ==

{{history|0.13.7|
* Updated stack inserter tech icon.}}

{{history|0.13.6|
* Now unlocked by their own research.}}

{{history|0.13.0|
* Introduced}}

== See also ==
* [[Stack filter inserter]]
* [[Transport network]]
* [[Electric network]]
* [[Inserters]]

{{LogisticsNav}}

[[Category:Items]]
[[Category:Transport network]]
[[Category:Crafting network]]
[[Category:Inserters]]

Achievements

2017-03-18T22:12:21Z

Kmkkmk: /* List of all achievements */

{{Languages}}

'''Achievements''' are given to the player when certain events happen or criteria is fulfilled. Some achievements are meant to make the player feel invested in the game. Others are meant to guide the player to use different strategies and optional game mechanics. Achievements are available in both the [http://store.steampowered.com/app/427520/ Steam] and standalone versions.

== Disabling achievements ==

Using the [[console]] or installing mods will disable achievements. A separate instance of achievements will be used when mods are installed and earned achievements will not register with Steam.

Enabling achievements again can be achieved by editing the binary data of a save. ([https://forums.factorio.com/viewtopic.php?f=5&t=29709&start=20 reference])

== List of all achievements ==
The search function of a browser may be used to find a specific achievement faster.

{| class="wikitable"
|-
! Achievement !! Icon !! Description
|-
| Automated cleanup || [[File:automated-cleanup-achievement.png|64x64px]] || De-construct 100 objects with the [[construction robot]]s.
|-
| Automated construction || [[File:automated-construction-achievement.png|64x64px]]||Construct 100 machines using robots.
|-
| Circuit veteran 1 || [[File:circuit-veteran-1-achievement.png|64x64px]] ||Produce 1.0k [[Advanced circuit]]s per hour.
|-
| Circuit veteran 2||[[File:circuit-veteran-2-achievement.png|64x64px]] ||Produce 10k [[Advanced circuit]]s per hour.
|-
| Circuit veteran 3|| [[File:circuit-veteran-3-achievement.png|64x64px]]||Produce 25k [[Advanced circuit]]s per hour.
|-
| Computer age 1 ||[[File:computer-age-1-achievement.png|64x64px]] || Produce 500 [[Processing unit]]s per hour.
|-
| Computer age 2|| [[File:computer-age-2-achievement.png|64x64px]]|| Produce 1.0k [[Processing unit]]s per hour.
|-
| Computer age 3|| [[File:computer-age-3-achievement.png|64x64px]]|| Produce 5k [[Processing unit]]s per hour.
|-
| Delivery service ||[[File:delivery-service-achievement.png|64x64px]] || Supply the player with 10k items delivered by the [[logistic robot]]s.
|-
| Eco unfriendly ||[[File:eco-unfriendly-achievement.png|64x64px]] || Research [[Oil processing]].
|-
| Getting on track like a pro||[[File:getting-on-track-like-a-pro-achievement.png|64x64px]] ||Build a [[Diesel locomotive]] within first 1 hour and 30 minutes of the game.
|-
| Getting on track||[[File:getting-on-track-achievement.png|64x64px]] ||Build a [[Diesel locomotive]].
|-
| Golem|| [[File:golem-achievement.png|64x64px]]||Take 500 [[damage]] in one hit and survive.
|-
| Iron throne 1||[[File:iron-throne-1-achievement.png|64x64px]] ||Produce 20k [[Iron plate]]s per hour.
|-
| Iron throne 2|| [[File:iron-throne-2-achievement.png|64x64px]]||Produce 200k [[Iron plate]]s per hour.
|-
| Iron throne 3||[[File:iron-throne-3-achievement.png|64x64px]] ||Produce 400k [[Iron plate]]s per hour.
|-
| It stinks and they don't like it|| [[File:it-stinks-and-they-dont-like-it-achievement.png|64x64px]]||Trigger an alien attack by pollution.
|-
| Lazy bastard || [[File:lazy-bastard-achievement.png|64x64px]]||Win the game by crafting no more than 111 items manually.
|-
| [[Logistic network]] embargo||[[File:logistic-network-embargo-achievement.png|64x64px]] ||Win the game without building [[Active provider chest]] and [[requester chest]].
|-
| Mass production 1||[[File:mass-production-1-achievement.png|64x64px]] ||Produce 10k [[Electronic circuit]]s.
|-
| Mass production 2||[[File:mass-production-2-achievement.png|64x64px]] ||Produce 1M [[electronic circuit]]s.
|-
| Mass production 3||[[File:mass-production-3-achievement.png|64x64px]] ||Produce 20M [[Electronic circuit]]s.
|-
| Minions||[[File:minions-achievement.png|64x64px]] ||Get 100 combat robots following you.
|-
| No time for chit-chat||[[File:no-time-for-chitchat-achievement.png|64x64px]] ||Finish the game in 15 hours. (Not available in peaceful mode.)
|-
| Pyromaniac||[[File:pyromaniac-achievement.png|64x64px]] ||Destroy 10k trees with fire.
|-
| Raining bullets|| [[File:raining-bullets-achievement.png|64x64px]]||Win the game without building [[Laser turret]]. (Not available in peaceful mode.)
|-
| Run Forrest run ||[[File:run-forrest-run-achievement.png|64x64px]] ||Destroy 100 trees by impact.
|-
| Smoke me a kipper, I'll be back for breakfast|| [[File:smoke-me-a-kipper-i-will-be-back-for-breakfast-achievement.png|64x64px]]||Finish the game.
|-
| So long and thanks for all the fish|| [[File:so-long-and-thanks-for-all-the-fish-achievement.png|64x64px]]|| {{spoiler|button-text=Spoiler! Click to view.|message=Send a raw fish into space via rocket.}}
|-
| Solaris||[[File:solaris-achievement.png|64x64px]] || Produce more than 10 GJ energy per hour without the usage of [[Steam engine]].
|-
| Steam all the way||[[File:steam-all-the-way-achievement.png|64x64px]] ||Win the game without using a [[solar panel]].
|-
| Streamrolled|| [[File:steamrolled-achievement.png|64x64px]]||Destroy 10 [[Spawners]] by impact.
|-
| Tech maniac||[[File:tech-maniac-achievement.png|64x64px]] ||Research all technologies.
|-
| There is no spoon|| [[File:there-is-no-spoon-achievement.png|64x64px]]||Finish the game in 8 hours. (Not available in peaceful mode.)
|-
| Trans factorio express|| [[File:trans-factorio-express-achievement.png|64x64px]]||Have a [[Train]] plans a path 1000 tiles long.
|-
| Watch your step||[[File:watch-your-step-achievement.png|64x64px]] ||Get killed by moving Locomotive.
|-
| You are doing it right!|| [[File:you-are-doing-it-right-achievement.png|64x64px]]||Construct more machines using robots than manually.
|-
| You've got a package ||[[File:you-have-got-a-package-achievement.png|64x64px]] || Supply the player by [[logistic robot]].
|-
|}

== History ==
{{history|0.13|
* Introduced}}

== See also ==

* [[Console]]
* [https://www.factorio.com/blog/post/fff-125 Friday Facts #125 - Achievements]

Tutorial:Transport use cases

2017-03-18T22:04:09Z

Kmkkmk: /* Trains */ remove repeated 'easily'

{{Languages}}
{{DISPLAYTITLE:What Transport for which case?|noerror}}
This page compares the three main [[transport]] methods: [[Belt transport system]] (conveyor belts), [[railway]] (trains) and [[Logistic robot|logistic robots]]. Note, that there are two more useful methods to transport items: The characters inventory and the [[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 ==

{| class="wikitable"
|-
! width=10% |
! width=30% | Belts
! width=30% | Trains
! width=30% | Logistic Robots
|-
| Throughput
| Constant, low for one belt, 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. There is a difference in using [https://forums.factorio.com/viewtopic.php?f=5&t=35806 Rollon-Rolloff-Stations (lot of space) or Terminus (much smaller)].
| 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 optimized, using chain signals. 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.
|-
| Parallelization
| High. Two parallel belts have the doubled throughput as one. Cost is also only double. On the other hand: Afford to build that doubles also.
| Extreme. Two parallel tracks can transport 5-10 times more trains than one, cause if a track is blocked the trains can choose the other free track and so they don't need to stop. The afford to build two tracks in parallel is lower than doubled.
| Not so good. Doubling the amount of bots from one to two surely doubles the throughput, but doubling robots from 500 to 1000 can result in complete chaos.
|-
| 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; which should be used for special cases only.
| Considerable amount of material is needed for initial locomotive. Small costs (when compared to the increase of transport) for making rails.
| Roboports and especially bots require a lot of resources to make. Logistic bot upgrades are very expensive, but needed and must be calculated into the total costs. Maintaining costs a lot of time.
|-
| 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.
|-
| Items in transit vs. duration of transport
| Bad. 100 tiles of belts stores about 700 items if fully loaded, but takes with basic belts 56 seconds for transport. With express belt, this is only 3 times faster.
| Very good. Lot of items transported in very short time.
| Chaotic. When jammed it can happen, that the most important items are unreachable in the air.
|-
| 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, bulk-goods (ores, some intermediates), 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
| Left/right lane problems (part of the game), splitting off the right amount of items.
| Deadlock situations (in complicated crossings), complex train-station and signal setup.
| Blocking of roboports by waiting for charging, "stupid" behavior that far away bots are used, instead of near and vice versa, Robots that take a "shortage" and cross a native village.
|}

== Experts ==

=== Belts ===

* Practical up to distances of 500 tiles (to compare: a radar station watches up to 200 tiles, with a 100-tile "radius").
* Useful for connecting 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.
* Best for working within an automated facility for '''bulk goods''', eg. transporting ore, plates, circuit boards, etc over short or medium distances.
* Store, over long distances, 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 on 500 tiles of [[basic belt]]s.
* 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:
* Belts have a constant throughput rate.
* Calculations are easily possible (such as "Do I need more belts to transport items from the mines?")
* Basic belts are cheap compared to tracks and and are easier to build
* You can easily see how much items are on the belt, which makes it easier to assess if you need more throughput.
* You can use the belt as an open storage: you can store about 72 items in a length of 10 belts, when using both lanes (but for long belts this is a big disadvantage!)

Disadvantages:
* Limited transport capacity, due to the limited throughput.
* Slow. This is a problem with very 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.
* Items on the belts are "lost items" until they are transported.

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 transport items from big and distant resource fields. No other mean of long distance transport is as fast as trains. A single train line can easily be build, however, planning an extensive railway setup can be difficult and time consuming. One clever way of placing rails can be done by entering a locomotive and placing the rails in front of it using the [[rail planner]].
* Trains can be used to connect separate factories together over long distances. This additionally lets you 'take a ride' out to outposts that require attention.

By smelting ore locally and shipping the plates via train, you can double your wagon capacity and route directly to a storage yard or factory.

=== Logistic robots ===

* 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 are terrible at long distances and bulk goods: It's not a good idea use bots for ore-transport or from/to furnaces. It is possible to use them for this task, but don't hold your breath for this to work perfectly; there are several issues with the AI that cause them to work inefficiently more often than not. Some players take that problem as challenge.
* They do a perfect job on bulk-goods, if they can charge between their jobs, which is the case on train-stations: Train comes in, train is unloaded, bots transports to the target chests, bots charge. Next rain comes in.
* Bots do a perfect job if you use them for random transport of expensive products; transport intermediate products 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 2000 items (ores) '''per wagon'''! And if you smelt the resources at your outpost and transport intermediate plates (copper, iron) you can transport 4000 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 robot]]s. 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 belt]]s should be use only for short sections.

=== 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 ==

* [http://www.factorioforums.com/forum/viewtopic.php?f=5&t=3948 Discussion about using conveyor belts vs. trains]. There are some interesting tips in this thread.
* [http://www.factorioforums.com/forum/viewtopic.php?f=18&t=5478 More trains vs. longer trains]
* [http://www.factorioforums.com/forum/viewtopic.php?f=18&t=5715 Deciding which items to re-make and which to keep on belts?]
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