Question: how many miles of track does csx have
[{'answer': '21,000 route miles', 'provenance': [{'wikipedia_id': '287679', 'title': 'CSX Transportation', 'start_paragraph_id': 1, 'start_character': 174, 'end_paragraph_id': 1, 'end_character': 192, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '287679', 'title': 'CSX Transportation', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 213, 'bleu_score': 0.65654065425462, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 18103689573654268660}, 'section': 'Section::::Abstract.'}]}]