Is Frostrail multiplayer?
Yes. The official Steam listing includes both single-player and online co-op. You can take the armored train into the wasteland alone or share the expedition with other players.
What co-op changes
Protect the lifeline
One player watches fuel, pressure, heat and repairs so the return route stays alive.
Call the retreat
Share health, weight and ammunition status before one player becomes the rescue mission.
Divide the haul
Split food, tools and salvage so one downed backpack does not take every option with it.
Cover the exit
A second gun matters most when the weather, enemies and inventory weight all push back.
How many players can join?
The 2026 Closed Beta allows an accepted tester to invite up to three friends, supporting a four-person group during this event. That should not be treated as a permanent final-game cap until FakeFish confirms shipping multiplayer limits.
Invited friends can also receive invitation capability during the Closed Beta. Find those invitations on the Steam game page.
Hosting, matchmaking and progression
Online co-op is confirmed, but final details around dedicated servers, public matchmaking, host migration and persistent shared progression are not yet stable enough to promise. During a test build, use the in-game report tools when a lobby fails instead of assuming the same behavior will ship.
Can you play alone?
Yes. Single-player is separately listed on Steam. Solo play concentrates every train, inventory and combat decision on you, while co-op turns resource planning and retreat timing into communication problems.