Simplify the following text for a Grade 6 native English-speaking person.
Original: On October 11 , 1883 , the heads of the major railroads met in Chicago at the former Grand Pacific Hotel to adopt the Standard Time System of four standard time zones for the continental U.S.A. . The new system was adopted by most states almost immediately after railroads did so .
Simplified: The owners of the major railroads met in Chicago to make the Standard Time System .