Question: How many different organizations own the railway lines which are a part of Norfolk Southern Railway?
SPARQL:
SELECT DISTINCT COUNT(?uri) WHERE { ?x <http://dbpedia.org/property/system> <http://dbpedia.org/resource/Norfolk_Southern_Railway> . ?x <http://dbpedia.org/property/owner> ?uri  . ?uri <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/Organisation>}