Original: Passenger levels decreased steadily from the late 1950s to late 1970s, but experienced a renaissance with the introduction of the high-speed Intercity 125 trains in the late 1970s and early 1980s.
Simplified: Passenger levels fell steadily from the late 1950s to late 1970s, but experienced a sharp increase after the introduction of the high-speed Intercity 125 trains in the late 1970s and early 1980s.