You can use GitLab CI/CD to automate your deployments on Railway by creating a project token and adding it to your repository secrets, then defining a workflow that triggers on pushes to the default branch, using the Railway CLI as a base image for a job that deploys to a service defined by the service ID. The entire building part is handled by Railway's build infrastructure, but you can still use GitLab CI to deploy build artifacts to Railway. It's recommended to keep the RAILWAY_TOKEN secret and pass the service ID freely as an environment variable or as part of the deploy command.