Simplify the following text for a Grade 6 native English-speaking person.
Original: The original all-steel 4,105-seat North stands were erected in 1958 , and in 1962 and 1968 the upper decks were added to the East and West sides , respectively , bringing capacity to its all-time high of 58,121 .
Simplified: The original all-steel 4,105-seat North stands were built in 1958 . In 1962 and 1968 the upper decks were added to the East and West sides bringing capacity to its all-time high of 58,121 .