Unified Train Logistics (UTL)

Automatic train logistics for Factorio 2.1: providers, requesters, depots, fuel stations,
cleanup and an overview window in one mod, built for high UPS.

Auf Deutsch lesen: README-de.md im GitHub-Repository.

📖 Wiki with pictures: github.com/Marcel1853/UTLogistics/wiki – every feature explained step by step, in
English and German, with screenshots. This page is the short version.

• Requires: Factorio 2.1, flib. Space Age is optional.
• Unlock: technology “Unified Train Logistics” (after automated rail transportation and
  circuit network). Upgrades: “UTL: Loading control” (wagon filters and job output) and
  “UTL: Network links I–III” (link a network with 1, 2 or 3 partner networks) and “UTL: Storage”
  (storage stations). The map
  setting “UTL features need research” turns this off – then everything is available right away.

Testing status. UTL runs through an automated self test (126 checks) and a headless load
test with 384 trains on 12 × 12 city blocks; updates are checked by loading a save from the
previous version. The main features are shown in the scenarios. In real games it has so far been
played on small networks. Newest: storage and cleanup gives back (0.0.8), topping up (0.0.7, off by default) and team separation (0.0.6, not yet tried in a
real multiplayer game). If something goes wrong, please report it in
the discussion – ideally with the save
and what you did. Keep a backup before adding UTL to a long-running base.

How UTL is made

I had tried to build my own train dispatcher several times before – it never quite worked out.
Then YouTuber fiftyshadesofgames was a bit frustrated with the other train dispatchers, and I
thought: come on, let's give it one more try 😄. So I started over from scratch, this time with
Claude Code – and with a lot of tests it finally came together.

UTL is written with the help of AI (Claude by Anthropic): the code and most texts – this README,
the wiki and the in-game help. I (Marcel) decide what UTL should do, open every scenario and my own
saves and test by hand before anything is released, so that as little as possible can break.

• Automated tests (run headless by the AI): self test with 126 checks, every tips & tricks
  scene, the load test with 384 trains and an update test with a save from the previous version.
• How often so far (counted from the development logs, 18 to 27 September 2026): the self test
  ran about 270 times, the tips & tricks test about 85 times, the load test about 90 times, plus
  more than 300 other headless Factorio runs (scenarios, update tests, checks).
• My own tests in the game: I start the scenarios and my saves again and again, check the
  windows and what the AI's tests say – so far I reported more than 60 bugs and findings back,
  with about 35 screenshots. How often I started the game myself I cannot say – I did not keep count.
  Some features are tested less than others – the testing status above
  says which.
• The test tools are part of the source: tools/
  on GitHub (self test, load test, tips & tricks test, screenshots).
• My PC is anything but a gaming rig: AMD Ryzen 3 2200G (4 cores), 14 GB usable RAM, no graphics
  card (only the graphics built into the CPU), Linux Mint. What runs smoothly here should run on
  most machines.

UTL lives from the ideas and bug reports of other players – the more come in, the better it gets.
Post them in the discussion.

Along the way, a Factorio modding skill for Claude came out of UTL: checked knowledge and test
tools that help the AI write Factorio mods. I am still working on it and would like to
publish it later.

Quick start

1. Depot: place a UTL train stop, open it, tick Depot.
2. Train: schedule with only the depot stop (any wait condition, e.g. inactivity 5 s),
   automatic mode. The train must be empty.
3. Provider: UTL train stop, tick Provider, wire a chest (red or green) to the stop.
   Inserters load the train.
4. Requester: UTL train stop, tick Requester. Click a request slot, pick an item,
   enter an amount (e.g. 8000 iron plates). Inserters unload the train.
5. Done: as soon as the requester is short enough, a free train goes depot → provider →
   requester → depot.

Tip: Shift + right-click a configured station and Shift + left-click another one to
copy all UTL settings (stop ↔ stop, combinator ↔ combinator). Blueprints and
Ctrl + C / Ctrl + V keep the settings as well.

Two station types, same logic

• UTL train stop: replaces the normal stop (can be built over it). Wires go to the stop.
  The UTL panel opens to the left of the train stop window (tabs “Station” and “Values”).
• UTL station combinator: belongs to a normal train stop – wire its output (red or green) to the stop. Chest wires go to the
  combinator input. Own window. Neither needs power.

Roles

Provider (positive signals are picked up), Requester (negative signals or request slots
are delivered), both = buffer, Depot (free trains wait here), Fuel station,
Cleanup (trains with leftover cargo are emptied here), Storage (takes in and gives out
between a minimum and a maximum stock, see below). Depot, fuel station and cleanup exclude each
other and provider/requester.

Requests are a target stock

The amount in a request slot is the stock you want to have. Only the difference
is delivered: demand = target − in stock − already in transit. A train is sent once the
demand reaches the requester threshold. Want several trains at once? Set a higher target.

Values

Min./max. train length (0 = any; also for depots, see below), max. trains, supply threshold /
stack threshold, provider priority, locked slots per wagon, demand threshold / stack threshold,
requester priority. The grey ⟲ button resets a value. Math works in every number field:
4000*2, 8000/4, (1+2)*3, 2^3, 1e3. The network name is explained in the next
section.

Networks

Every station has one network name (field “Network” in its window, empty = default). Stations,
depots, fuel stations and cleanups only work with the exact same name – so one map can carry
several separate systems, each with its own depot, fuel station and cleanup. Leave the field empty
everywhere for one big network. A typo or a capital letter is a different network.

Linking networks (research “UTL: Network links I–III”, 1–3 partners): linked networks help
each other with trains, depots, fuel stations and cleanups. A link is a star – one center,
partners that help the center and are helped by it, but not each other; a network belongs to at
most one star, links count per surface. Set it up in the station window (“Linked with”) or in the
UTL Manager, tab “Networks”. Example: a depot in its own network Reserve linked to Ore and
Plates serves both, while ore and plate stations still ignore each other.

More, with examples and all messages: wiki – Networks.

Mixed providers

Needs research: “UTL: Loading control”.

A provider may keep several goods in one chest:

• Wagon filters (no wiring): while a delivery runs, UTL sets the wagon slots to the goods of that
  job, so a plain inserter from a mixed chest loads only what was ordered. Off per station or map-wide;
  wagons you filtered yourself are never touched.
• Job output: a small output next to every stop carries the running jobs as signals – goods to
  load here positive, goods arriving negative; while a delivery train stands there also train number,
  length, locomotives, wagons, “train loads here” and “train unloads here”. Use it for filter
  inserters, displays and pumps (fluids have no slot filters). Do not wire it to the station's input.

More, with examples: wiki – Mixed providers and job output.

How trains run

• UTL does not overwrite your schedule: provider and requester are inserted as
  temporary stops that vanish after departure. Train groups and interrupts are kept.
• A rail waypoint in front of each stop makes the train use exactly that stop, even if several
  stops share the name.
• The train waits at the provider until the ordered amount is loaded, at the requester until
  it is empty.
• Selection: highest provider priority and amount, then a free train that carries as much as
  possible in one trip and is close; reachability is checked with the pathfinder.
• Reservations prevent several trains from being sent for the same demand.
• Several items per train, fluids (fluid wagons, one fluid per delivery) and next job
  right away after unloading or cleanup/fuel stations (map setting).
• The stop's train limit (vanilla) applies on top of “max. trains”.

Refueling

If any locomotive is below 40 % (map setting “Refuel below (%)”), the train visits the nearest
fitting fuel station – before its next job, after unloading or from the depot – and waits until
all locomotives are full or nothing changed for 30 s. Without a free fuel station a low train waits
in the depot; a network with no UTL fuel station at all refuels your way (interrupts, by hand).
Min./max. train length on fuel stations separates small and large trains.

Cleanup

Trains with leftover cargo (back in the depot with cargo, canceled delivery, not fully unloaded) go
to the nearest fitting cleanup station. Its window sets what it accepts: All items / All
fluids (default) or single goods; if one station is not enough, the train visits several. Fluids:
pumps into a storage tank, one cleanup per fluid.

Cleanup gives back. With “Offer contents again” a cleanup offers its chest contents like a
provider – only as a fallback, like any provider or empty first. Leftovers are not
brought back to the same requester for 5 minutes. Map setting: “Cleanup may offer its contents again”.

More: wiki – Fuel, cleanup and depots.

Storage (for advanced players)

Needs research: “UTL: Storage”.

A storage takes in and gives out – a buffer close to the consumers. Per good (up to eight) a
minimum and a maximum: below the minimum it requests up to the maximum, above the minimum it
offers the rest like a normal provider. Two storages never shove goods back and forth. With
“Accept leftover cargo” (on) trains may drop leftovers there, too. Map setting: “Allow storage
stations”.

Inserters in both directions (vanilla, one side of the track): unloading inserter → chest →
transfer inserter → chest → loading inserter. Wire the job output to the unloading and loading
inserters: loading [utl-loading] > 0, unloading [utl-loading] = 0. Scenario “UTL storage”
shows it.

Depots and train length

Free trains wait empty at stops with the Depot role – every depot stop needs the
role, the name alone is not enough; a train that ends up at a stop with a depot's name but
without the role (also vanilla stops) moves on to a free real depot of that name. If a train
arrives at a depot whose min./max. length does
not fit, it moves to a free matching depot with the same name; if there is none, it stays
and remains available.

UTL Manager

Open with the locomotive button in the shortcut bar or Ctrl + Shift + U (or Ctrl + Alt + U).
Tabs: Depots, Stations, Networks, Inventory (click a good for details), History
(last 100 deliveries), Alerts (last 100), Settings. Search by station name, click a station to
see it on the map, click a train to follow it. With Space Age a drop-down picks the planet.

Alerts come as regular Factorio alerts in three groups – no suitable train (after 5 minutes),
leftover/missing cargo, train problems – each can be turned off per player.

More: wiki – UTL Manager and alerts.

Map settings

The most important ones: next job right away (on), load only the current job (on),
job output (on), UTL features need research (on), refuel below (40 %), loading /
unloading inactivity (30 s each, combined with the cargo by or or and), top up while
loading (off), cleanup may offer its contents again (on), allow storage stations (on).
The loading values can also be set in the UTL Manager, tab “Settings” – per team with teams;
admins use /utl-admin.

All settings: wiki – Settings.

Performance

Measured headless (no graphics, so no FPS) with the load test scenario:

UTL itself peaks at about 13 ms when it sends trains (sending triggers the game's pathfinding).
Most of the time is spent by the game's own trains (movement and pathfinding).

Important: the map is otherwise almost empty (no factory, belts or biters) – the numbers show
what UTL and the trains need, not the UPS of a whole megabase.

Scenarios

New game → Scenarios (everything researched, cheat mode on, display panels with explanations):

• UTL examples (mixed provider) – mixed provider with the job output, two goods in one trip,
  oil and water with switched pumps.
• UTL network links – four networks, a star with a partner that has no trains of its own.
• UTL teams – four teams with the same station and network names; /utl-team rot switches.
• UTL top up (to watch) – with and without topping up, round by round, with an explanation window.
• UTL storage (to watch) – new in 0.0.8: storage, a cleanup that gives back and four small
  example lines, with an explanation window.
• UTL planet test (Space Age) – the same network on Nauvis, Vulcanus and Gleba.
• UTL load test (384 trains) – 12 × 12 city blocks for measuring, with storages, cleanups that
  give back, linked networks, topping up and fixed train lengths; starts in a few seconds.

Details and pictures: wiki – Scenarios and tips.

Tips & tricks

The in-game Tips & tricks menu has a Unified Train Logistics category: seventeen entries,
each with a running example scene – from the first delivery to networks, cleanup giving back,
storage and the manager.

After an update, UTL writes one short line into the chat with the most important news; the link in
it opens the tips & tricks page “New in UTL”. Switch it off per player: Update notes in chat.

FAQ

Questions and troubleshooting step by step: wiki – FAQ and troubleshooting.

Teams and surfaces

Teams (forces) and surfaces are kept apart: trains, depots, fuel and cleanup stations only
work within their own team and surface, network links count per team, and the manager shows only
your team. Two teams may use the same names. Trains cannot change planet, so every surface needs its
own depots and trains. Try it: scenario “UTL teams”.

Topping up while loading (optional, off by default)

If a requester's demand grows while its train is still heading to the provider or loading there,
the amount is added to the running load list instead of a second trip (same provider, room in
the train, fluids only of the same kind). It keeps the train longer at the provider, so it is off
by default – map setting or manager “Settings”: Top up while loading. Scenario “UTL top up”
shows it.

Not yet included

Collecting from a second provider on the way (one trip still picks up at exactly one provider).

For mod authors

Remote interface utl (station data, deliveries, alerts, configuring stations and requests, network
links, team and map values, tagging script-made blueprints): wiki – For mod authors.