Trainco is a private company, so they would be responsible for posting on their buildings. Not posted, it is assumed OK to carry. However, doesn't the State of Ohio have an inspection facility on the Trainco campus? I don't know about that. And, IANAL.
"The Constitution shall never be construed to prevent the people of the United States who are peaceable citizens from keeping their own arms."
- Samuel Adams, Massachusetts Ratifying Convention, 1788