In a lot of cases, that’s true; the railroad does not hold the title for the land. In the case of a railroad, in the US, we’re generally talking about an “easement in gross” (as opposed to an easement appurtenant.) An easement in gross is one that is attached to a person or entity, in our case, the railroad company, instead of some particular patch of real estate. For railroads, this easement is commercial.
Although the railroad may not hold actual title of the land, it is considered to be private property by both the RR and the state. They have the right to post it, patrol it, use it for whatever purpose the easement grants, including building and maintaining the infrastructure. They can prosecute you as a tresspassor, because the easement applies to them, not you.
As far as re-negotiating, easement rights are alienable, or transferrable.
Sometimes it becomes neccessary to re-negotiate, such as when the term of use expires.
In the case of my railroad, we own the vast majority of our land outright. However, there is one section that is on another person’s property. When the railroad was built, the original owner of that property granted the easement to build and operate a railroad on his land. We have a swath, about 10 feet wide. If we need to do tie repair or anything, we do not need his permission to do so. If we see a random person walking the tracks along our easement, we prosecute them for tresspassing. Likewise, if our neighbor dismantled any of our track, or cut a tree down over it, we could prosecute him. He can be on our easement (which he technically owns) so long as he doesn’t pose a danger to our operation. He cannot plant trees, crops, or build fences in it, though. He can move animals and equipment over our easement to get to the rest of his property, so long as it’s done safely and does not interfere with our operation.
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