Before you start
You must administer the server, know its allocated addresses and ports, and have the .sav file you want to import. Keep an independent copy of the existing world. This documentation does not open ports or execute commands on production services.
Compare versions and protect administration
Record client and server builds before changing files. Add the service address and port in Server Manager, then set a name and administrator password when claiming a new server. Player access uses a separate password setting. Do not give every participant administrative rights as a shortcut to joining. Confirm the relevant platform and dedicated-server support before planning the group’s session.
Understand the two current port roles
Documentation separates the standard port, default 7777, using UDP for gameplay and TCP for server traffic and the HTTPS API, from the reliable messaging port, default 8888 over TCP. That means two port numbers but three protocol bindings. Old 15000 and 15777 lists are not a current reference. A successful TCP test does not automatically validate UDP or the separate reliable channel.
Use panel allocations rather than changing the host network
On hosted services, use the values assigned to your server. Do not open a broad port range or change the host machine’s firewall. For an installation you administer yourself, documentation distinguishes Port, ReliablePort and ExternalReliablePort. The standard and reliable ports do not have the same redirection rules. Have a custom mapping validated rather than assume that every internal port can be remapped arbitrarily.
Import a save without replacing your original
Keep the original .sav outside the server. Use Server Manager’s import feature where supported by your version, taking care to select the intended session. If manual transfer is necessary, stop writes first and identify the directory actually in use. Do not replace active session files while the server writes them. Check loading, important factory structures and a player connection after the import.
Check pause behaviour, resources and mods
A persistent session retains the world, but automatic pause can stop simulation when nobody is connected. Set that option to suit the project rather than assume uninterrupted production by default. Machines, trains and logistics change CPU, memory and save demands. For mods, explicitly verify dedicated-server support, game branch and dependencies: support in a player’s client alone does not validate a server installation.
Investigate stalled loading with specific evidence
If Server Manager responds but loading stalls, record the time, build, assigned ports and last relevant log message. Ask support to verify the reliable channel alongside the standard port. If only one save has the problem, preserve it and report that distinction rather than overwrite it with an empty world. Repeat the same connection test after one targeted correction and keep your recovery copies intact.
For your situation
| Situation | Next check |
|---|---|
| Server Manager responds but joining stalls | Compare versions and access, then have the allocated reliable messaging channel checked. |
| An existing factory needs importing | Copy the .sav first and inspect the loaded world before inviting the group back. |
| Production stops when nobody is connected | Check automatic pause in Server Manager and whether the server is actually running. |
Official sources
These documents describe the relevant protocols and software. Your service terms and configuration still need to be checked.