Of course, no matter which path you choose, you'll need to make sure it's possible to access Trains Server ports ( 8080 , 8081 , 8008 ) using the server's external IP.
In GCP, you can do that by choosing " Allow HTTP Access " when creating a new instance (easy, but less secure), or set up a more detailed and secure firewall rules that will only allow access to ports 8080 , 8081 and 8008 (you can consult GCP documentation for that).