Here’s some background based on my understanding of railroad easements:
An easement is a right to use somebody else’s land for some specified purpose without having full ownership of it. Many, but not all*, U.S. railroad right of ways are actually easements across the private property of the owners of adjacent land. The way the typical railroad easement works is that the initial railroad obtains temporary rights to use land in order to construct and operate a railroad across somebody’s property, in exchange for some form of compensation (such as a one-time monetary transfer to the property owner or the right of the property owner to receive the benefits of rail service).
The easement exists as long as the railroad is in operation, and can be transferred to successor companies (railroads that buy out other railroads). But, as soon as the railroad is abandoned, as is common with all kinds of easements granted to a particular entity for a particular use, the easement is extinguished and full ownership of the land upon which the right of way exists is supposed to revert to the current owners of the adjacent land (split down the center if separate parties own land on each side of where the tracks were). This is based on old English common law precedent pertaining to easements before railroads even existed, but specific statutes dealing with railroad right of way easements were written to formalize the precedent in the United States.
Railbanking was a radical change to the way railroad right of way easements were traditionally treated in the United States. The idea is that without railbanking, abandoned railroad lines will be broken up and redeveloped by the people who take ownership of the property. Railbanking is supposed to keep the right of way intact, and also allows it to be used for other linear infrastructure, such as recreational trails (“Rails to Trails”).
The problem is that railbanking ignores established property precedent, and the original intent of easements to be extinguished when the easement holder discontinues use. Furthermore, railbanking can force property owners to accept what are basically new terms not mentioned in the original easement when the right of way is put to use for something like a trail or a pipeline rather than the rail service specified in the easement. Similar problems have occurred in the past when active railroads have allowed telecommunications companies to install cable within railroad right of ways, without the actual property owner’s agreement.
Railbanking is basically a workaround for governments to take control of unused railroad right of ways without extinguishing the original easement and forming a new one, and without compensating the actual property owner for new uses such as trails. Compensation, in the “takings clause” of the fifth amendment is an important part of the constitution that requires governments to pay for depriving an owner of the use of their property.
So what will happen? The supreme court could rule that rails-to-trails in combination with railbanking is perfectly okay, in which case nothing will change. The supreme court is good at making rulings that take no strong position one way or the other- they don’t usually want to shock the system. So no existing bike paths are in danger of being shut down. However, they could easily rule that compensation to property owners is required when existing easements are taken for trails. This would mean that property owners must be compensated whenever new bike paths are built across private property, and may even retroactively entitle property owners to compensation for paths that have already been built on their property. No doubt, this would put the brakes on some new bike path proposals where easements are involved.
As a railfan, I am conflicted about railbanking. While I hate to see the obliteration of any potentially productive rail corridor (most abandoned ones aren’t), I favor strict property rights more. I definitely think that property owners should be compensated when easements are taken over for bike paths or any other use that was not mentioned in the original easement.
*Some right of ways were granted directly to the initial railroad company by a state or federal government when the land was previously unowned, while the full ownership of some right of ways were negotiated for (or seized) by railroads and deeded to them. These possibilities would not likely be affected by a ruling on easements.