Transport Fever 3 Lithuania map and how to make your own

The towns ate my country

I loaded my brand new Lithuania into Transport Fever 3 and the whole island turned grey.

Street grids everywhere. I asked for 33 towns and got 33 towns, each about 100 times bigger than I wanted. Vilnius took it well. The farmland did not.

Video thumbnail: Game crashed, over the AI's in-game panel and the crash dialog — Video I'm teaching AI to play on this map. Three AIs, one crash. It loads from YouTube only when you press play.

That was the first of three ways this map broke. It works now, it's free, and the same recipe will build a map of your own country. Claude has since been running a whole transport company on it, badly. That story is in I let Claude run a Transport Fever 3 company for 26 years.

The map on the Mod Hub
The source on GitHub, with the build scripts

Update: five more countries

Germany got a lot of downloads on its first day, so I ran the same recipe on the other countries where the game is most popular. Each is the whole country as an island, with real rivers, towns where they really are and starter industries. I made the Alps about 500 m tall, which plays better than the real 3 km, and kept the Netherlands almost flat.

Deutschland: Germany, 60 towns
Schweiz: Switzerland, 36 towns, Alps and lakes
Österreich: Austria, 40 towns, the Danube
Magyarország: Hungary, 40 towns, Lake Balaton
Nederland: Netherlands, 45 towns, big rivers, flat land

The build scripts and heightmaps for all of them are in the country maps repo. Each map's install steps list its own minimum and maximum height for the import.

What you get

Lithuania as an island. Real terrain, the Nemunas and Neris rivers dug wide enough for ships, and 33 real towns in their real places, sized by population. Vilnius starts with 581 residents, Kaunas with 316, Klaipėda with 162. There are 16 starter industries and a set of Lithuanian town names. The roads between towns are yours to build.

Make your own, in six steps

Nothing here is specific to Lithuania. Swap in any country.

Pick a square. The game wants a square map, 16.384 km on a side, with a 4097 by 4097 pixel heightmap. Cut a 420 km square around your country.
Download the elevation. The free Terrain Tiles on AWS hide a height in every pixel: R × 256 + G + B / 256 − 32768 metres. Stitch them, halve the heights so hills don't become cliffs, and save a 16-bit grayscale PNG.
Make it an island. Everything outside the border sinks into a beach and shallow sea. The coast is fiction, and it plays better.
Dig the rivers. At this scale a real river is a few pixels wide. Draw the OpenStreetMap river lines wider and down to sea level so ships can use them.
Place the towns. OpenStreetMap has every town and most populations. I divided the population by 1,000 for the starting size, with a minimum of 25.
Add industries by hand. Farms, forests, sawmills, food, breweries. Nobody has data for this, so it's game design.

Shaded relief map of Lithuania as an island with town dots and labels, sea all around — DiagramThe map as data, before the game touches it. Not an in-game image.

Let Claude do the typing

I built mine by working with a coding assistant, and these prompts are close to what I'd give it again. Use Claude Code or any assistant that can run code and look at the files it makes. The important part is the last sentence of each: make it check its own work.

1. The terrain

I'm making a Transport Fever 3 map of [COUNTRY]. Write a Python script
that downloads the AWS Terrain Tiles (terrarium encoding, zoom 9) for a
420 km square around the country, decodes each pixel to metres with
R*256 + G + B/256 - 32768, stitches them, resamples to 4097 x 4097,
smooths it slightly, halves the heights, and saves a 16-bit grayscale
PNG where the lowest point is -12 m and the highest 180 m. Then open
the PNG and tell me whether the coast and the biggest river look right.

2. The island and the rivers

Using the Natural Earth border for [COUNTRY], sink everything outside
the border into a gentle beach and shallow sea so the country becomes
an island. Using OpenStreetMap river lines for [RIVER NAMES], draw them
wider and carve them down to sea level so ships can use them. Render a
preview image with the coastline and rivers so I can check it.

3. The towns

Query OpenStreetMap through Overpass for place=city and place=town
nodes in [COUNTRY]. Convert each position to game metres on the same
square as the heightmap: centre at 0,0, 16384 m wide, east positive,
north positive. Nudge any town that lands on water. Size each town as
its population tag divided by 1000, minimum 25. Write a Lua file in
the exact format of the Transport Fever 3 Map Editor's towns and
industries export (a data() function returning towns and industries).
Then list every town with no population tag and confirm every town
is on dry land.

Once you have a map you like, open it in the game's Map Editor and use the Export button in the towns and industries tool. The game writes the exact file format, including the cargo needs that I forgot at first. Hand that file back to your assistant as the example for next time.

Three ways it broke

Towns 100 times too big. My import code edited the game's list of planned towns, then asked the game for that list again to build them. The game hands you a fresh copy every time, so my changes vanished. The fix was to pass the edited list straight to the build command.

Before

Aerial view with huge grey town grids covering much of the land around a river

After

Aerial view with small towns and farm fields beside a river

Towns that wanted nothing. With the sizes right, the towns just sat there. No needs, nothing to deliver. I had never told them what they need. Now every town asks for vegetables in its shops and planks in its industry.

A world with no towns at all. My very first town file had no data() function, which is what the game calls to read it. No error, no crash, just an empty country.

So now every map gets imported into a clean world, and I read the towns, heights and needs back from the running game before anyone else sees it.

Install and play

Subscribe on the Mod Hub. Open the Lietuva map page, or search "Lietuva" in the game's Mod Hub. This adds the Lithuanian town names.
Download the map files. Get the zip from GitHub. Copy everything in mod/map-kit/heightmaps into the heightmaps folder and everything in mod/map-kit/towns_industries into towns_industries. Both are inside your Transport Fever 3 userdata folder, Steam/userdata/<your id>/3493540/local.
Start a new Map Editor map: Temperate, Very Large, 1:1. Pick the Lietuviški / Lithuanian names.
Import the heightmap Lietuva_4097_playable.png with minimum −12, maximum 180, water level 0. Press Return after typing each number, or the old value stays and your mountains come out about 16 times too tall.
Import the towns Lietuva_33_towns_starter_industries.
Connect the towns, save the map and start a game.

Kaunas on a small peninsula where two rivers meet, with a large complex to the south — ScreenshotKaunas, where Nemunas meets Neris. Transport Fever 3, 27 Oct.

A mod is a folder: mod.json, a _metadata folder with modinfo.json and 1920 by 1080 images (0.png is the cover), and your content. Copy it into staging_area in your userdata folder, open Mod Hub, then My Mods, log in to mod.io, tick Set Public and upload. Names can't pass 32 characters and summaries 100. The Mod Hub rejects .js and .html files inside a mod, so keep scripts out. Before you publish, check mod IDs, paths and your default company name for anything personal.

To update later, raise revision in mod.json and put your mod's number in _metadata/mod.io_fileid.txt. Replace the staging folder and that file goes with it, so your next upload would create a duplicate page.