Complex sentence: The original system consisted of nine vehicles, with an additional three added in the mid- 1970s, and was designed to have a capacity of 14,400 passengers per hour and travel at a maximum speed of.
Split into simpler sentences: The original system consisted of nine vehicles; an additional three were added in the mid- 1970s. The system was designed to have a capacity of 14,400 passengers per hour and travel at a maximum speed of.