three.js · sandbox · built phone first

Kleinbahn

An island-railway sandbox in three.js, built for phones.

This is the game, not a video. Drag to look around, pinch or scroll to zoom, and tap the plus button to build.

The demo loads from tiny-train.beacon.host, and only after you press play.

Kleinbahn is a sandbox. There is no score and no goal. You shape islands, lay track and roads, and place things: stations, houses, a harbour, a lighthouse, a volcano. The game adds people, cars and boats around them.

It is made for a phone held in one hand. The game is one self-contained HTML file. An island can be shared as a link or a QR code.

The video shows the sample island that the game starts with.

Trains and trackSwitches, bridges, stations and trains that stop for each other.
The islandTowns, people, cars, level crossings, harbours and drawbridges.
EventsA volcano, a shuttle launch, an airship, hot-air balloons and a fire brigade.
Time and weatherDay and night, four seasons, rain and clouds. In autumn there is a ghost train ride.
Shared playOne island kept the same on several devices.

How it changed

One entry per merged pull request that changed play, newest first. Each clip is filmed from the game at the state of that pull request.

10 Nov 2026 · PR #14

Every player steers

In shared play every player can steer a plane, the airship, a car or a boat. In the clip a second player, Mia, flies a plane, and the host follows her.
- A plane or the airship has one pilot at a time.
- A chip for each player shows what the player does. A tap follows the player.
- An arrow at the screen edge points to each player out of sight.
10 Nov 2026 · PR #13

An airfield

A runway, hangars, a tower and five planes that take off, fly a route with a loop and land in turn. The clip shows one of them in its loop.
- One plane tows a banner.
- Pilot mode: fly a plane or the airship with one stick.
- Drive a car, a bicycle or a boat yourself.
- Cars drive only to places their road network reaches.
10 Nov 2026 · PR #11

Fires in shared play

The host starts a fire, and every guest sees the same house burn and the fire brigade drive out.
- Island links and saves are checked before they load.
- An island link asks before it replaces your island.
- The QR code is drawn offline.
8 Nov 2026 · PR #9

New icons

All 60 icons were drawn again, centred and sized for phones. The clip opens the build dial.
- Each dial item shows its name under the icon.
- Larger touch targets.
- The dial no longer runs past the screen edge.
8 Nov 2026 · PR #8

Rooms that survive a reload

When the host stops, every guest goes home at once. In the clip the guest is on the host’s island without trees, the host closes the room, and the guest’s own island comes back.
- A host that reloads opens the same room again.
- A guest that loses the host waits and joins again by itself.
8 Nov 2026 · PR #7

Player names

A player can give a name. It shows in the player list and in the follow bar: here the host follows Mia.
8 Nov 2026 · PR #3

See the other players

A pin in each player’s colour stands where that player looks. In the clip the pin of a guest moves across the island.
- Follow another player’s view.
- The host can make a guest view only, or send it away.
8 Nov 2026 · PR #2

The host decides when things move

Eruptions, launches and flights start on the host and reach every guest. Here the game is a guest: the host starts an eruption, and the guest’s volcano erupts with the same lava.
- Airships and balloons keep the host’s position.
- Trains keep their place on the host’s path.
8 Nov 2026 · PR #1

Shared play

One player hosts and friends join by link or QR code. In the clip a second player plants trees, and they appear on the host’s island.
- Remote edits go into the undo history, so an undo takes back only your own change.
- A guest never saves. Its own island comes back when it leaves.
- Every message from another player is checked.
7 Nov 2026 · Starting point

The island as it was imported

The first commit of this repository brought the game with its earlier work: trains, towns, the seasons and events such as this volcano.