Complex sentence: The two former-SP&S freighthouses were listed on the National Register of Historic Places in 1996, as the North Bank Depot Buildings, and at that time they were vacant and had not yet been renovated.
Split into simpler sentences: The two former-SP&S freighthouses were listed on the National Register of Historic Places in 1996, as the North Bank Depot Buildings. At that time, they were vacant and had not yet been renovated.