Complex sentence: The line has hump-backed stations to allow trains to store gravitational potential energy as they slow down and release it when they leave a station, providing an energy saving of 5% and making the trains run 9% faster.
Split into simpler sentences: The line has hump-backed stations to allow trains to store gravitational potential energy as they slow down and release it when they leave a station. This provides an energy saving of 5% and makes the trains run 9% faster.