Complex sentence: Repairs on the Wollman Rink in Central Park, built in 1955, were started in 1980 by a general contractor unconnected to Trump, with an expected-year construction schedule, but were not completed by 1986.
Split into simpler sentences: Repairs on the Wollman Rink in Central Park, built in 1955, were started in 1980 by a general contractor unconnected to Trump. Despite an expected-year construction schedule, the repairs were not completed by 1986.