Hosting and Joining

Everybody starts MPFever.exe (see Installation). Transport Fever 3 starts by itself. In the game's main menu, click the Multiplayer card (top left): the multiplayer page opens. Type your player name at its top right.

Hosting a game

1. Tab Host a game: choose the Company mode:
   • One company for everybody: all players run the same company.
   • One company per player: every other player gets a company of their own, with a starting capital, and picks its colour in the lobby. The host chooses after how many months a company in debt goes bankrupt.
2. Click Host under the savegame to share. Any of your savegames works, even one made without MPFever. The field at the right of the list filters the savegames by name.
3. The lobby opens on the same page and lists the players who join.
   • Click Invite Steam friends, or let your friends right-click you in their Steam friends list and choose « Join game ».
   • The lobby lists the mods of your savegame and shows each player the ones missing on their PC.
4. When everybody is there, click Start the game: every player receives your savegame and every game loads it at the same time. Close the lobby cancels.

Joining a game

Any of these:

• Accept the host's Steam invitation, or right-click the host in your Steam friends list and choose « Join game ». Transport Fever 3 and MPFever start by themselves if needed, and the multiplayer page opens by itself.
• Tab Public servers: the dedicated servers open to everybody, with their players, world, company mode, a padlock when they ask for a password, and their message of the day. Click Join (with a password, the Join a game tab opens with the address filled in: type the password there). A server of another MPFever version is greyed out. The list reads itself again every 20 seconds, or at once with Refresh.
• Tab Join a game: type the host's address (for example 89.12.34.56 or 89.12.34.56:28090), then Join. A dedicated server may ask for a Password: type it before Join.

In the lobby, wait for the host to start the game. The host's game is sent to you, with the progress on the page, and loads by itself. If you already have the host's savegame on your PC, nothing is downloaded.

Missing mods are installed by themselves when you join, through the game's Mod Hub (mod.io or Steam Workshop; you must be signed in to it). A mod that no Mod Hub has can be sent by the host, after you accept.

You can also join a game that is already running: every game pauses, reloads the host's game for a moment, and everybody continues together.

Network: do I need to open a port?

Through Steam: no. Since 0.5.3 the host's game also listens on Steam (Steam's peer-to-peer connections and its relays). A Steam invitation, or « Join game » in the Steam friends list, uses it with no port to open. MPFever tries Steam and the direct address at the same time, and keeps a direct connection when there is one.

By address, the host needs one of these:

• Port forwarding: TCP port 28090 forwarded to the host's PC, and MPFever.exe allowed in the Windows firewall (tick « Private » and « Public » the first time). MPFever asks the router to open it by itself while a session runs (UPnP or NAT-PMP). The launcher's log says whether that worked.
• A virtual LAN (Radmin VPN, ZeroTier, Tailscale...): every player joins the same network, and the host gives the address that tool shows.
• The same local network: the host's local address (for example 192.168.1.20).
• IPv6: the host also accepts players over IPv6. To join by hand, put the address in brackets: [2a02:...]:28090.

During the game

• Play normally. Anybody can build, buy vehicles, create lines... A build appears on every game after a second or two: every game applies it at the same game time.
• Speed and pause: use the game's own speed buttons. Every game always runs at the same speed.
• Responsive builds (experimental, host setting, off at first): in ⚙ Settings, the host can turn it on. Your builds then show at once on your game instead of after a second or two, so you can attach the next piece right away; the other games apply them at the same game time as before.
• The MPFever window: an icon in the bottom bar, left of Earnings, opens it. It has the tabs Session (players, sync state, speed, Steam invites, Report a problem; the host also has Resynchronise), Chat, Company and Rules (one company per player only), and Settings.
• If the games differ, MPFever corrects it by itself: money at once, anything else with a resynchronisation. See Troubleshooting and Reports.
• Connection drop: if a player's connection drops for a moment, the host waits for them up to 60 seconds. The other players see « lost the connection: the game waits for them ». Back in time, the player catches up and the game goes on with no reload. After 60 seconds, the player joins again as a new join.
• To stop: the host saves the game (a normal save), then everybody quits. Closing the game also closes MPFever.

One company per player

• Every window of a station, depot, vehicle, line or building says on its first line which company owns it.
• Rules tab: every company sets a rule for its tracks, its stations and stops, and its depots: open (the default), private, or with a toll. Fees and tolls show in the finance window.
• Company tab: a table of the companies (money, rank, lines, vehicles), money gifts between companies, and several players in one company.
• Contracts and loans belong to each company.
• Bankruptcy: a company whose money stays below zero for the months the host chose goes bankrupt, and its assets are auctioned.

Dedicated server

A PC of its own can run the world for everybody, with nobody playing on it: download MPFever-<version>-server.zip. Its folder is called MPFever-Server, and its MPFever.exe opens the server's window (start-server.bat does the same).

• The window opens with the server stopped. Click Start with display (the game's window shows the world) or Start without display (the game runs hidden and silent and does not draw the world: far less work for the PC; a graphics card is still needed). Both run the same world and the same saves.
• Tick Start the server when MPFever opens to have it start by itself, the way it was started last (off at first).
• Stop saves the world and stops the server; the window stays open for a new start. Closing the window stops everything.
• The world waits (paused) while nobody is connected, is saved every 10 minutes, and is started again after a crash.
• It has a console (start, start headless, say, save, pause, speed, kick, resync, restart, stop, exit...), a password, a maximum number of players and a message of the day.
• Public server list: while its world runs, the server shows in the Public servers tab of every player's multiplayer page (its name, players, world, company mode, password or not, message of the day). It is on at first: public=false in mpfever_server.properties keeps the server out of the list. public-address= gives the address players should use (a domain name), else the list uses the server's public IP address.
• The server PC runs the full game with its own Steam account and copy of the game.

Players join it from the Public servers tab, or by its address like they join a host. Setup and settings: see SERVER.txt in the server archive.