I have been reading some "after action reports" from visitors and they seem to be a bit confused, so, let me sort this out...
The Strasburg Railroad, the Railroad Museum of Pennsylvania and the Cherry Crest Farm (Amazing Maize Maze) while they are close to each other are owned by separate organizations.
The SRR is owned by a privately held corporation. The RMPA is owned by the State Government and the Cherry Crest Farm is owned by an Amish family.
Each venue charges a separate admission fee for each person to each facility. However, there may be package deals available on the day you arrive. Inquire at the SRR ticket office.