In Monopoly, the rent for owning one railroad with no other railroads is $25.
Each of the four railroad title deeds uses the same rent schedule. One railroad earns $25, two earn $50, three earn $100, and owning all four earns $200 when another player lands on one of them. The schedule rewards collecting railroads without requiring houses or hotels.
Railroads are distinct from colored properties. They cannot be developed with houses, and their rent is determined solely by how many railroads the owner controls. The four classic railroad names are Reading Railroad, Pennsylvania Railroad, B&O Railroad, and Short Line.
The $25 amount applies when the owner has exactly one railroad. It is not the purchase price, which is $200, and it is not the rent after a player has collected multiple railroads.