>>16697125 (OP)No and that's just not how things work. There are software updates that they can push trough while live and technically some systems can be maintained but that's only because they consists of multiple smaller systems that they shut down for the maintenance like computer servers where they switch out the racks one at a time.
There's not much point in trying to engineer a machine where a guy runs around it switching oils or what ever while it works, it's just too dangerous and doesn't offer nearly enough benefit.