Complex sentence: Grating was retrofitted to prevent risk takers sliding down the 100ft high girders holding up the walkways, and cast iron grills were erected to stop thoroughfare by over exuberant youths racing their bikes and skateboards along the perfectly smooth walkway racetrack.
Split into simpler sentences: Grating was retrofitted to prevent risk takers sliding down the 100ft high girders holding up the walkways. Cast iron grills were erected to stop thoroughfare by over exuberant youths racing their bikes and skateboards along the perfectly smooth walkway racetrack.