I believe modern economists are studying how ownership should be assigned. The thinking is that contracts and rules handle the majority of situations but emergencies and edge cases require an owner who has authority and whose interests align with the thing they control. And you want a mechanism to reassign ownership when the previous owner is incompetent.

In the case of a national train system, you may want to create a national entity to develop, coordinate, and make the physical trains and support technologies. You would create regional or metro entities to control the train network for their local area including the train stations. They coordinate with each other via negotiated contracts. Any edge cases or emergency falls under the purview of the owning entity. For example, the national entity controls the switch from diesel locomotives to the newest engine. The local authority is responsible for repairing the lines after a natural disaster.

If an entity is egregiously incompetent or failing, the national regulatory authority, with support of the majority of all the different train entities, takes control and reforms it.