We occasionally initiate deployments to migrate services between hosts for infrastructure maintenance, security patches, or workload distribution optimization, and Hobby tier services may be moved during these operations. These are documented in our Railway initiated deployments section. The restarts you saw on March 31 were part of this process, not triggered by any action on your end.

Ok, good to know. Can I stop the services, or pause them somehow? From the deploy tab I can only see the Delete option.

To stop a running service without deleting it, click the three dots on the active deployment in the Deployments tab and select "Remove" - this stops the deployment and moves it to history while keeping the service itself intact. Since you mentioned your subscription is ending in April, your services will also be stopped automatically when the plan expires.